2014 |
Echeveste, Jose Ignacio; Gonzalez-de-Aza, Miguel A; Zapata, Juan AEP and Mutual Coupling Formulation for Antenna Array Synthesis via Convex Optimization Artículo en actas 2014 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 1732-1733, Inst Elect Elect Engineers; Inst Elect Elect Engineers Antennas & Propagat Soc 2014, ISSN: 1522-3965, (IEEE Antennas-and-Propagation-Society International Symposium (APSURSI), Memphis, TN, JUL 06-11, 2014). @inproceedings{EchevesteGuzman2014, title = {AEP and Mutual Coupling Formulation for Antenna Array Synthesis via Convex Optimization}, author = {Jose Ignacio Echeveste and Miguel A Gonzalez-de-Aza and Juan Zapata}, issn = {1522-3965}, year = {2014}, date = {2014-01-01}, booktitle = {2014 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI)}, pages = {1732-1733}, organization = {Inst Elect Elect Engineers; Inst Elect Elect Engineers Antennas & Propagat Soc}, series = {IEEE Antennas and Propagation Society International Symposium}, abstract = {This work proposes the integration of an electromagnetic analysis of a finite array through infinite array results and an array beampattern synthesis methodology from linear programming. The periodic radiating elements are characterized from a full wave and modular procedure based on domain decomposition, 3D-FEM, modal analysis and matrix formulation. The technique takes into account real radiating patterns of antennas with complex geometry and the mutual coupling between the array elements.}, note = {IEEE Antennas-and-Propagation-Society International Symposium (APSURSI), Memphis, TN, JUL 06-11, 2014}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This work proposes the integration of an electromagnetic analysis of a finite array through infinite array results and an array beampattern synthesis methodology from linear programming. The periodic radiating elements are characterized from a full wave and modular procedure based on domain decomposition, 3D-FEM, modal analysis and matrix formulation. The technique takes into account real radiating patterns of antennas with complex geometry and the mutual coupling between the array elements. |
Corcoles, Juan; Gonzalez-de-Aza, Miguel A; Zapata, Juan Full-wave analysis of finite periodic cylindrical conformal arrays with Floquet spherical modes and a hybrid finite element - generalized scattering matrix method Artículo de revista JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, 28 (1), pp. 102-111, 2014, ISSN: 0920-5071. @article{Corcoles2014, title = {Full-wave analysis of finite periodic cylindrical conformal arrays with Floquet spherical modes and a hybrid finite element - generalized scattering matrix method}, author = {Juan Corcoles and Miguel A Gonzalez-de-Aza and Juan Zapata}, doi = {10.1080/09205071.2013.857280}, issn = {0920-5071}, year = {2014}, date = {2014-01-01}, journal = {JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS}, volume = {28}, number = {1}, pages = {102-111}, abstract = {This work reports a novel approach for the full-wave analysis of a finite conformal array made up of antennas which are periodically arranged on a metallic cylindrical surface. The analysis methodology is based on a hybrid finite element and modal analysis method, and it allows the computation of the generalized scattering matrix of the structure. In this case, spherical vector modes are used to characterize the radiating region and because of the periodic nature of the conformal array, Floquet's theory is used to render the methodology efficient and accurate. Therefore, the formulation is derived to be able to characterize the whole structure from the analysis of only one semi-period. Numerical results of arrays made up of rectangular apertures and microstrip patches are presented and compared with the ones obtained with commercial software and infinite models both for conformal and planar arrays.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work reports a novel approach for the full-wave analysis of a finite conformal array made up of antennas which are periodically arranged on a metallic cylindrical surface. The analysis methodology is based on a hybrid finite element and modal analysis method, and it allows the computation of the generalized scattering matrix of the structure. In this case, spherical vector modes are used to characterize the radiating region and because of the periodic nature of the conformal array, Floquet's theory is used to render the methodology efficient and accurate. Therefore, the formulation is derived to be able to characterize the whole structure from the analysis of only one semi-period. Numerical results of arrays made up of rectangular apertures and microstrip patches are presented and compared with the ones obtained with commercial software and infinite models both for conformal and planar arrays. |
Florencio, Rafael; Boix, Rafael R; Carrasco, Eduardo; Encinar, Jose A; Barba, Mariano; Pérez-Palomino, Gerardo Broadband reflectarrays made of cells with three coplanar parallel dipoles Artículo de revista 2014. @article{, title = {Broadband reflectarrays made of cells with three coplanar parallel dipoles}, author = {Rafael Florencio and Rafael R Boix and Eduardo Carrasco and Jose A Encinar and Mariano Barba and Gerardo Pérez-Palomino}, doi = {10.1002/mop.28171}, year = {2014}, date = {2014-01-01}, abstract = {A broadband reflectarray cell made of three parallel dipoles printed on a dielectric layer is presented. A 33% bandwidth is achieved for the cell made of dipoles, which is larger than that obtained for a reference cell consisting of three stacked square patches (26%). Using this cell, a 41‐cm reflectarray antenna has been designed to produce a collimated beam at 9.5 GHz. The numerical results obtained for the reflectarray antenna made of parallel dipoles show a 1‐dB bandwidth of 19%, a 65% efficiency, 0.2 dB of losses, and low levels of cross polarization (25 dB below the maximum). These results demonstrate a high performance for the proposed reflectarray antenna made of cells with three printed dipoles.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A broadband reflectarray cell made of three parallel dipoles printed on a dielectric layer is presented. A 33% bandwidth is achieved for the cell made of dipoles, which is larger than that obtained for a reference cell consisting of three stacked square patches (26%). Using this cell, a 41‐cm reflectarray antenna has been designed to produce a collimated beam at 9.5 GHz. The numerical results obtained for the reflectarray antenna made of parallel dipoles show a 1‐dB bandwidth of 19%, a 65% efficiency, 0.2 dB of losses, and low levels of cross polarization (25 dB below the maximum). These results demonstrate a high performance for the proposed reflectarray antenna made of cells with three printed dipoles. |
Florencio, Rafael; Perez-Palomino, Gerardo; Encinar, Jose A; Boix, Rafael R Broadband Reflectarray Element for Dual Polarization Made of Orthogonal Sets of Parallel Dipoles Artículo en actas 8th European Conference on Antennas and Propagation, EUCAP 2014, (The Hague, The Netherlands), 2014. @inproceedings{, title = {Broadband Reflectarray Element for Dual Polarization Made of Orthogonal Sets of Parallel Dipoles}, author = {Rafael Florencio and Gerardo Perez-Palomino and Jose A Encinar and Rafael R Boix}, year = {2014}, date = {2014-01-01}, booktitle = {8th European Conference on Antennas and Propagation, EUCAP 2014, (The Hague, The Netherlands)}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Abdo-Sánchez, E; Martín-Guerrero, T M; Page, J E; Esteban, J; Camacho-Peñalosa, C On the Feasibility of the Complementary Strip-Slot Element to Build Planar Series-fed Arrays Artículo de revista IJMOT, International Journal of Microwave and Optical Technology, 9 (1), pp. 24-28, 2014. @article{AbdoSanchez2014b, title = {On the Feasibility of the Complementary Strip-Slot Element to Build Planar Series-fed Arrays}, author = {E Abdo-Sánchez and T M Martín-Guerrero and J E Page and J Esteban and C Camacho-Peñalosa}, url = {http://www.ijmot.com/ijmot/uploaded/1453019006.pdf}, year = {2014}, date = {2014-01-01}, journal = {IJMOT, International Journal of Microwave and Optical Technology}, volume = {9}, number = {1}, pages = {24-28}, abstract = {The equivalences between evanescent TM modes and negative permeability media and between periodic thin-wires structures and electric plasmas have been exploited, in order to design a periodic square waveguide that supports a backward-wave TM mode, whose equivalent transmission line can be considered as a Left-Handed Transmission Line (LHTL). Realizable waveguide fillings are proposed, and some theoretical and experimental results are presented. How to extract the macroscopic parameters of the implemented artificial dielectric plasmas is also shown.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The equivalences between evanescent TM modes and negative permeability media and between periodic thin-wires structures and electric plasmas have been exploited, in order to design a periodic square waveguide that supports a backward-wave TM mode, whose equivalent transmission line can be considered as a Left-Handed Transmission Line (LHTL). Realizable waveguide fillings are proposed, and some theoretical and experimental results are presented. How to extract the macroscopic parameters of the implemented artificial dielectric plasmas is also shown. |
Abdo-Sánchez, E; Esteban, J; Martín-Guerrero, T M; Camacho-Peñalosa, C; Hall, P S A Novel Planar Log-Periodic Array Based on the Wideband Complementary Strip-Slot Element Artículo de revista IEEE Transactions on Antennas and Propagation, 62 (11), pp. 5572-5580, 2014, ISSN: 0018-926X. @article{AbdoSanchez2014a, title = {A Novel Planar Log-Periodic Array Based on the Wideband Complementary Strip-Slot Element}, author = {E Abdo-Sánchez and J Esteban and T M Martín-Guerrero and C Camacho-Peñalosa and P S Hall}, doi = {10.1109/TAP.2014.2357414}, issn = {0018-926X}, year = {2014}, date = {2014-01-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {62}, number = {11}, pages = {5572-5580}, abstract = {A novel microstrip log-periodic array based on the broadly-matched complementary strip-slot radiating element is proposed. The array consists of microstrip-fed log-periodically-scaled slots on the ground plane and their complementary stubs on the microstrip layer. Since the radiating element is not resonant, the analysis differs from the previously reported log-periodic arrays. Low scale factor ($tau$) with high radiation efficiency is possible, since the element radiation efficiency is not resonant and the relative spacing ($sigma$) does not have to be selected for good matching, because the element is intrinsically matched. A design example with $tau =0.909$, $sigma=0.17$ and 15 elements has been analyzed. The achieved bandwidth goes from 2.7 to 8.7 GHz, with a radiation efficiency and a gain of better than 85% and 5 dB, respectively. Moreover, the antenna can be terminated in an open circuit without affecting its performance. Simulated and experimental results show that the radiation pattern is stable over frequency. A method for computing the radiation pattern using equivalent circuits as well as results with a reflector plane for cancelling the beam in one half-space are also included. Due to the good performance, simplicity and low cost, this antenna can be suitable for broadband applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel microstrip log-periodic array based on the broadly-matched complementary strip-slot radiating element is proposed. The array consists of microstrip-fed log-periodically-scaled slots on the ground plane and their complementary stubs on the microstrip layer. Since the radiating element is not resonant, the analysis differs from the previously reported log-periodic arrays. Low scale factor ($tau$) with high radiation efficiency is possible, since the element radiation efficiency is not resonant and the relative spacing ($sigma$) does not have to be selected for good matching, because the element is intrinsically matched. A design example with $tau =0.909$, $sigma=0.17$ and 15 elements has been analyzed. The achieved bandwidth goes from 2.7 to 8.7 GHz, with a radiation efficiency and a gain of better than 85% and 5 dB, respectively. Moreover, the antenna can be terminated in an open circuit without affecting its performance. Simulated and experimental results show that the radiation pattern is stable over frequency. A method for computing the radiation pattern using equivalent circuits as well as results with a reflector plane for cancelling the beam in one half-space are also included. Due to the good performance, simplicity and low cost, this antenna can be suitable for broadband applications. |
Robustillo, Pedro; Zapata, J; Encinar, Jose A; Florencio, Rafael; Boix, Rafael R; Mosig, J R Accurate Characterization of Multi-Resonant Reflectarray Cells by Artificial Neural Networks. Artículo en actas 2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1935-1937, 2014, ISSN: 2164-3342, (8th European Conference on Antennas and Propagation (EuCAP), Hague, NETHERLANDS, APR 06-11, 2014). @inproceedings{Robustillo2014, title = {Accurate Characterization of Multi-Resonant Reflectarray Cells by Artificial Neural Networks.}, author = {Pedro Robustillo and J Zapata and Jose A Encinar and Rafael Florencio and Rafael R Boix and J R Mosig}, issn = {2164-3342}, year = {2014}, date = {2014-01-01}, booktitle = {2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, pages = {1935-1937}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {This paper describes the accurate characterization of the reflection coefficients of a multilayered reflectarray element by means of artificial neural networks. The procedure has been tested with different RA elements related to actual specifications. Up to 9 parameters were considered and the complete reflection coefficient matrix was accurately obtained, including cross polar reflection coefficients. Results show a good agreement between simulations carried out by the Method of Moments and the ANN model outputs at RA element level, as well as with performances of the complete RA antenna designed.}, note = {8th European Conference on Antennas and Propagation (EuCAP), Hague, NETHERLANDS, APR 06-11, 2014}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This paper describes the accurate characterization of the reflection coefficients of a multilayered reflectarray element by means of artificial neural networks. The procedure has been tested with different RA elements related to actual specifications. Up to 9 parameters were considered and the complete reflection coefficient matrix was accurately obtained, including cross polar reflection coefficients. Results show a good agreement between simulations carried out by the Method of Moments and the ANN model outputs at RA element level, as well as with performances of the complete RA antenna designed. |
Carrasco, Eduardo; Low, T; Perruisseau-Carrier, J Dynamic light bending with graphene plasmonic structures Artículo en actas International Conference on Metamaterials, Photonic Crystals and Plasmonics, 2014. @inproceedings{Carrasco2014, title = {Dynamic light bending with graphene plasmonic structures}, author = {Eduardo Carrasco and T Low and J Perruisseau-Carrier}, year = {2014}, date = {2014-01-01}, booktitle = {International Conference on Metamaterials, Photonic Crystals and Plasmonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2013 |
Leal-Sevillano, Carlos A; Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Experimental comparison of waveguide filters at W-band implemented by different machining processes and split-block Artículo de revista JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, 27 (18), pp. 2390-2394, 2013, ISSN: 0920-5071. @article{LealSevillano2013, title = {Experimental comparison of waveguide filters at W-band implemented by different machining processes and split-block}, author = {Carlos A Leal-Sevillano and Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1080/09205071.2013.851011}, issn = {0920-5071}, year = {2013}, date = {2013-12-01}, journal = {JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS}, volume = {27}, number = {18}, pages = {2390-2394}, abstract = {The aim of this work is to explore different machining processes and different split-block, getting important experimental information for the design of passive waveguide components at W-band. To this end, two all-pole response filters are machined by different techniques: electro-discharge and milling, and split-block: H-plane and E-plane. Some interesting results, obtained in the design, fabrication, and measure of waveguide filters at W-band, such as tolerances of the different processes and level of insertion loss, are reported.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aim of this work is to explore different machining processes and different split-block, getting important experimental information for the design of passive waveguide components at W-band. To this end, two all-pole response filters are machined by different techniques: electro-discharge and milling, and split-block: H-plane and E-plane. Some interesting results, obtained in the design, fabrication, and measure of waveguide filters at W-band, such as tolerances of the different processes and level of insertion loss, are reported. |
Leal-Sevillano, Carlos A; Pisano, Giampaolo; Montejo-Garai, Jose R; Maffei, Bruno; Ruiz-Cruz, Jorge A; Ng, Ming Wah; Rebollar, Jesus M Development of low loss waveguide filters for radio-astronomy applications Artículo de revista INFRARED PHYSICS & TECHNOLOGY, 61 , pp. 224-229, 2013, ISSN: 1350-4495. @article{LealSevillano2013a, title = {Development of low loss waveguide filters for radio-astronomy applications}, author = {Carlos A Leal-Sevillano and Giampaolo Pisano and Jose R Montejo-Garai and Bruno Maffei and Jorge A Ruiz-Cruz and Ming Wah Ng and Jesus M Rebollar}, doi = {10.1016/j.infrared.2013.08.012}, issn = {1350-4495}, year = {2013}, date = {2013-11-01}, journal = {INFRARED PHYSICS & TECHNOLOGY}, volume = {61}, pages = {224-229}, abstract = {In this paper the modeling, fabrication and experimental characterization of a wideband band-pass filter operating in W-band (75-110 GHz) is presented. This new high-performance waveguide filter can have several potential applications and will particularly be relevant in radio-astronomy receivers. The classical direct coupled cavity-based synthesis is first used. Then, an efficient full-wave analysis based on the mode matching technique is carried out, leading to a tenth order all-pole filter design. Two different prototypes were fabricated using an accurate electroforming machining technique. A good agreement between simulation and measurements is obtained with negligible frequency shift and 15 dB return loss level. One should note the low level of insertion loss reported of about 0.4 dB within the band-pass, which is a critical parameter for low-noise receivers. (C) 2013 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper the modeling, fabrication and experimental characterization of a wideband band-pass filter operating in W-band (75-110 GHz) is presented. This new high-performance waveguide filter can have several potential applications and will particularly be relevant in radio-astronomy receivers. The classical direct coupled cavity-based synthesis is first used. Then, an efficient full-wave analysis based on the mode matching technique is carried out, leading to a tenth order all-pole filter design. Two different prototypes were fabricated using an accurate electroforming machining technique. A good agreement between simulation and measurements is obtained with negligible frequency shift and 15 dB return loss level. One should note the low level of insertion loss reported of about 0.4 dB within the band-pass, which is a critical parameter for low-noise receivers. (C) 2013 Elsevier B.V. All rights reserved. |
Abdo-Sánchez, E; Camacho-Peñalosa, C; Martín-Guerrero, T M; Esteban, J; Page, J E Multiband Circularly-Polarized Planar Array Based on the Complementary Strip-Slot Element Artículo en actas 43rd European Microwave Conference (EuMC), pp. 652-655, Nuremberg (Germany), 2013, (ISBN: 978-2-87487-031-6). @inproceedings{AbdoSanchez2013a, title = {Multiband Circularly-Polarized Planar Array Based on the Complementary Strip-Slot Element}, author = {E Abdo-Sánchez and C Camacho-Peñalosa and T M Martín-Guerrero and J Esteban and J E Page}, year = {2013}, date = {2013-10-01}, booktitle = {43rd European Microwave Conference (EuMC)}, pages = {652-655}, address = {Nuremberg (Germany)}, abstract = {The concept of a circularly-polarized planar array based on the use of the complementary strip-slot element is explored. This element is a conventional microstrip-fed slot that overcomes its narrow bandwidth by using a strip superimposed onto it. The array is fed in a traveling-wave configuration and a ring shape is used to provide the required circular polarization with the sequential rotation technique. A design example is analysed by electromagnetic simulation. Thanks to the broadlymatched strip-slot element, multiband behaviour with axial ratio below 3 dB, good matching (better than 15 dB) and high radiation efficiency is obtained at 6.2, 8.9 and 12.3 GHz. This novel antenna offers design flexibility with a very simple structure.}, note = {ISBN: 978-2-87487-031-6}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The concept of a circularly-polarized planar array based on the use of the complementary strip-slot element is explored. This element is a conventional microstrip-fed slot that overcomes its narrow bandwidth by using a strip superimposed onto it. The array is fed in a traveling-wave configuration and a ring shape is used to provide the required circular polarization with the sequential rotation technique. A design example is analysed by electromagnetic simulation. Thanks to the broadlymatched strip-slot element, multiband behaviour with axial ratio below 3 dB, good matching (better than 15 dB) and high radiation efficiency is obtained at 6.2, 8.9 and 12.3 GHz. This novel antenna offers design flexibility with a very simple structure. |
Florencio, Rafael; Boix, Rafael R; Encinar, Jose A Enhanced MoM Analysis of the Scattering by Periodic Strip Gratings in Multilayered Substrates Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (10), pp. 5088-5099, 2013, ISSN: 0018-926X. @article{Florencio2013, title = {Enhanced MoM Analysis of the Scattering by Periodic Strip Gratings in Multilayered Substrates}, author = {Rafael Florencio and Rafael R Boix and Jose A Encinar}, doi = {10.1109/TAP.2013.2273213}, issn = {0018-926X}, year = {2013}, date = {2013-10-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {61}, number = {10}, pages = {5088-5099}, abstract = {The method of moments (MoM) is applied to the analysis of the scattering of a multilayered periodic strip grating by a plane wave with oblique incidence and arbitrary polarization. Although this problem has been traditionally solved by means of the MoM in the spectral domain, this is an approach which leads to the computation of slowly convergent infinite summations. In this paper, the problem is solved by means of the mixed potential integral equation (MPIE) formulation of the MoM in the spatial domain. While applying the MoM in the spatial domain, two improvements are introduced which lead to important CPU time savings. First, the multilayered periodic Green's functions are accurately interpolated in terms of Chebyshev polynomials. Second, half the integrals involved in the computation of the MoM matrix entries are obtained in closed form. As a consequence of these two improvements, the spatial domain version of the MoM presented in this paper turns out to be between one and two orders of magnitude faster than the conventional spectral domain version when basis functions that account for edge singularities are used in the modeling of the current density on the metallizations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The method of moments (MoM) is applied to the analysis of the scattering of a multilayered periodic strip grating by a plane wave with oblique incidence and arbitrary polarization. Although this problem has been traditionally solved by means of the MoM in the spectral domain, this is an approach which leads to the computation of slowly convergent infinite summations. In this paper, the problem is solved by means of the mixed potential integral equation (MPIE) formulation of the MoM in the spatial domain. While applying the MoM in the spatial domain, two improvements are introduced which lead to important CPU time savings. First, the multilayered periodic Green's functions are accurately interpolated in terms of Chebyshev polynomials. Second, half the integrals involved in the computation of the MoM matrix entries are obtained in closed form. As a consequence of these two improvements, the spatial domain version of the MoM presented in this paper turns out to be between one and two orders of magnitude faster than the conventional spectral domain version when basis functions that account for edge singularities are used in the modeling of the current density on the metallizations. |
Leal-Sevillano, Carlos A; Cooper, Ken B; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer Artículo de revista IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY, 3 (5), pp. 574-583, 2013, ISSN: 2156-342X. @article{LealSevillano2013b, title = {A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer}, author = {Carlos A Leal-Sevillano and Ken B Cooper and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.1109/TTHZ.2013.2264317}, issn = {2156-342X}, year = {2013}, date = {2013-09-01}, journal = {IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY}, volume = {3}, number = {5}, pages = {574-583}, abstract = {In this paper, we present the modeling and experimental validation of an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz. While duplexers based on ferrite circulators are key components of many monostatic radar systems, at W-band frequencies and above the performance of waveguide circulators rapidly deteriorates. The design presented here uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations. The circular polarization is efficiently generated in waveguide using a septum orthomode transducer polarizer, leading to a compact device with a single horn antenna. The complete duplexer is designed using efficient numerical algorithms, resulting in a fabricated device with a measured 10% fractional bandwidth, a return loss better than 20 dB, isolation of 30 dB, and insertion loss below 1 dB.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, we present the modeling and experimental validation of an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz. While duplexers based on ferrite circulators are key components of many monostatic radar systems, at W-band frequencies and above the performance of waveguide circulators rapidly deteriorates. The design presented here uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations. The circular polarization is efficiently generated in waveguide using a septum orthomode transducer polarizer, leading to a compact device with a single horn antenna. The complete duplexer is designed using efficient numerical algorithms, resulting in a fabricated device with a measured 10% fractional bandwidth, a return loss better than 20 dB, isolation of 30 dB, and insertion loss below 1 dB. |
Leal-Sevillano, Carlos A; Reck, Theodore J; Jung-Kubiak, Cecile; Chattopadhyay, Goutam; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M Silicon Micromachined Canonical E-Plane and H-Plane Bandpass Filters at the Terahertz Band Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 23 (6), pp. 288-290, 2013, ISSN: 1531-1309. @article{LealSevillano2013c, title = {Silicon Micromachined Canonical E-Plane and H-Plane Bandpass Filters at the Terahertz Band}, author = {Carlos A Leal-Sevillano and Theodore J Reck and Cecile Jung-Kubiak and Goutam Chattopadhyay and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.1109/LMWC.2013.2258097}, issn = {1531-1309}, year = {2013}, date = {2013-06-01}, journal = {IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, volume = {23}, number = {6}, pages = {288-290}, abstract = {In this letter, several bandpass filters operating in the WR-1.5 band (500 to 750 GHz) are presented. The deep reactive ion etching (DRIE) silicon micromachining process is used for the fabrication of the filters. Two canonical filter topologies based on E- and H-plane are implemented. The work presented here has two specific objectives: a) to get important fabrication process parameters, such as tolerances, vertical angles, surface roughness, and repeatability and b) to validate the proper working of the waveguide filters in the terahertz band. These filters do not have any tuning element. Experimental results show better than 10 dB return loss and approximately 1 and 2.5 dB insertion loss (for 6% fractional bandwidth) for the E- and H-plane topology, respectively. The obtained results are in agreement with fabrication tolerances of 2 mu m and vertical angles deviations up to 3 degrees.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this letter, several bandpass filters operating in the WR-1.5 band (500 to 750 GHz) are presented. The deep reactive ion etching (DRIE) silicon micromachining process is used for the fabrication of the filters. Two canonical filter topologies based on E- and H-plane are implemented. The work presented here has two specific objectives: a) to get important fabrication process parameters, such as tolerances, vertical angles, surface roughness, and repeatability and b) to validate the proper working of the waveguide filters in the terahertz band. These filters do not have any tuning element. Experimental results show better than 10 dB return loss and approximately 1 and 2.5 dB insertion loss (for 6% fractional bandwidth) for the E- and H-plane topology, respectively. The obtained results are in agreement with fabrication tolerances of 2 mu m and vertical angles deviations up to 3 degrees. |
Florencio, Rafael; Boix, Rafael R; Carrasco, Eduardo; Encinar, Jose A; Losada, Vicente Efficient numerical tool for the analysis and design of reflectarrays based on cells with three parallel dipoles Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 55 (6), pp. 1212-1216, 2013, ISSN: 0895-2477. @article{Florencio2013a, title = {Efficient numerical tool for the analysis and design of reflectarrays based on cells with three parallel dipoles}, author = {Rafael Florencio and Rafael R Boix and Eduardo Carrasco and Jose A Encinar and Vicente Losada}, doi = {10.1002/mop.27533}, issn = {0895-2477}, year = {2013}, date = {2013-06-01}, journal = {MICROWAVE AND OPTICAL TECHNOLOGY LETTERS}, volume = {55}, number = {6}, pages = {1212-1216}, abstract = {In this article, the Method of Moments in the spectral domain (MoM-SD) is applied to the analysis of multilayered periodic structures, containing three coplanar parallel dipoles in the unit cell. It is shown that the use of basis functions with edge singularities in the modeling of the current density on the dipoles leads to important computer memory and CPU times savings in the analysis of the periodic structures. The MoM-SD home-made software is used in the analysis of a shaped beam reflectarray antenna made of cells with three parallel dipoles under the local periodicity assumption. The numerical results obtained for the radiation pattern of the antenna are compared with numerical results provided by the commercial software CST (R) and with measurements and good agreement is found. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:12121216, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27533}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, the Method of Moments in the spectral domain (MoM-SD) is applied to the analysis of multilayered periodic structures, containing three coplanar parallel dipoles in the unit cell. It is shown that the use of basis functions with edge singularities in the modeling of the current density on the dipoles leads to important computer memory and CPU times savings in the analysis of the periodic structures. The MoM-SD home-made software is used in the analysis of a shaped beam reflectarray antenna made of cells with three parallel dipoles under the local periodicity assumption. The numerical results obtained for the radiation pattern of the antenna are compared with numerical results provided by the commercial software CST (R) and with measurements and good agreement is found. (c) 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:12121216, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27533 |
Carrasco, Eduardo; Barba, Mariano; Encinar, Jose A; Arrebola, Manuel; Rossi, Francesco; Freni, Angelo Design, Manufacture and Test of a Low-Cost Shaped-Beam Reflectarray Using a Single Layer of Varying-Sized Printed Dipoles Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (6), pp. 3077-3085, 2013, ISSN: 0018-926X. @article{Carrasco2013, title = {Design, Manufacture and Test of a Low-Cost Shaped-Beam Reflectarray Using a Single Layer of Varying-Sized Printed Dipoles}, author = {Eduardo Carrasco and Mariano Barba and Jose A Encinar and Manuel Arrebola and Francesco Rossi and Angelo Freni}, doi = {10.1109/TAP.2013.2254431}, issn = {0018-926X}, year = {2013}, date = {2013-06-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {61}, number = {6}, pages = {3077-3085}, abstract = {This paper presents the design, manufacture and test of a low-cost reflectarray antenna that provides a sectored-cosecant squared beam. The bandwidth limitation of single-layer reflectarrays is overcome by using three parallel dipoles in each cell. First, the relative length of the three dipoles is chosen to improve the element bandwidth. Then, the dipole dimensions are adjusted to generate a sectored beam in azimuth and cosecant squared in elevation. A prototype has been manufactured and tested. The measured radiation pattern has been compared with the results of approximate and full-wave numerical methods. The influence of the grounded substrate used to fix the antenna structure has also been investigated. Both experimental and simulation results demonstrate the capabilities of the proposed single-layer configuration to provide a shaped-beam on a 10% bandwidth and low losses. This antenna can be a low-cost alternative to multilayer configurations for communication and radar applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper presents the design, manufacture and test of a low-cost reflectarray antenna that provides a sectored-cosecant squared beam. The bandwidth limitation of single-layer reflectarrays is overcome by using three parallel dipoles in each cell. First, the relative length of the three dipoles is chosen to improve the element bandwidth. Then, the dipole dimensions are adjusted to generate a sectored beam in azimuth and cosecant squared in elevation. A prototype has been manufactured and tested. The measured radiation pattern has been compared with the results of approximate and full-wave numerical methods. The influence of the grounded substrate used to fix the antenna structure has also been investigated. Both experimental and simulation results demonstrate the capabilities of the proposed single-layer configuration to provide a shaped-beam on a 10% bandwidth and low losses. This antenna can be a low-cost alternative to multilayer configurations for communication and radar applications. |
Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Leal-Sevillano, Carlos A; Rebollar, Jesus M Modelling of dual-polarisation diplexers based on enhanced multiport turnstile junctions Artículo de revista IET MICROWAVES ANTENNAS & PROPAGATION, 7 (7), pp. 485-492, 2013, ISSN: 1751-8725. @article{MontejoGarai2013, title = {Modelling of dual-polarisation diplexers based on enhanced multiport turnstile junctions}, author = {Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Carlos A Leal-Sevillano and Jesus M Rebollar}, doi = {10.1049/iet-map.2012.0424}, issn = {1751-8725}, year = {2013}, date = {2013-05-01}, journal = {IET MICROWAVES ANTENNAS & PROPAGATION}, volume = {7}, number = {7}, pages = {485-492}, abstract = {The modelling of waveguide diplexers working simultaneously with two dual-polarisation signals is presented in this study. The proposed network is an ortho-mode junction with six physical ports based on an enhanced multiport turnstile junction. This structure is excited at the common port coming from the antenna, by two signals at different frequency bands which are required to be discriminated into dedicated ports. The added functionality of the structure presented in this work is that each frequency band can also allocate two orthogonal polarisations (dual linear or dual circular) with a very large separation between bands (fractional bandwidth larger than 55%), using two different waveguiding concepts. The first one is based on confining the high frequencies at the centre of the axial path. The second one is just the dual, diverting the high frequencies to the outer boundaries of the axial path. The proposed structures, whose modelling and design will be addressed, are suited for low insertion loss and high-power applications, since they do not use metallic pins, irises or small waveguide sections. Moreover, as consequence of the introduced waveguiding concepts, they are very compact and short in the axial direction, which is crucial for this type of feeders in satellite applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The modelling of waveguide diplexers working simultaneously with two dual-polarisation signals is presented in this study. The proposed network is an ortho-mode junction with six physical ports based on an enhanced multiport turnstile junction. This structure is excited at the common port coming from the antenna, by two signals at different frequency bands which are required to be discriminated into dedicated ports. The added functionality of the structure presented in this work is that each frequency band can also allocate two orthogonal polarisations (dual linear or dual circular) with a very large separation between bands (fractional bandwidth larger than 55%), using two different waveguiding concepts. The first one is based on confining the high frequencies at the centre of the axial path. The second one is just the dual, diverting the high frequencies to the outer boundaries of the axial path. The proposed structures, whose modelling and design will be addressed, are suited for low insertion loss and high-power applications, since they do not use metallic pins, irises or small waveguide sections. Moreover, as consequence of the introduced waveguiding concepts, they are very compact and short in the axial direction, which is crucial for this type of feeders in satellite applications. |
Abdo-Sánchez, E; Page, J E; Martín-Guerrero, T M; Esteban, J; Camacho-Peñalosa, C The Complementary Strip-Slot as a Broadband Planar Array Element Artículo en actas Proceedings of the IX Iberian Meeting on Computational Electromagnetics (EIEC), Denia, Alicante (Spain), 2013. @inproceedings{AbdoSanchez2013c, title = {The Complementary Strip-Slot as a Broadband Planar Array Element}, author = {E Abdo-Sánchez and J E Page and T M Martín-Guerrero and J Esteban and C Camacho-Peñalosa}, year = {2013}, date = {2013-05-01}, booktitle = {Proceedings of the IX Iberian Meeting on Computational Electromagnetics (EIEC)}, address = {Denia, Alicante (Spain)}, abstract = {A novel planar radiating element that enhances signigicantly the impedance bandwidth of the microstrip radiators has been already demonstrated by the authors. This element is similar to a slot etched on the ground plane of a microstrip line, with the peculiarity of having superimposed onto it its complementary stub. This paper reviews the main characteristics of the complementary strip-slot element and describes its use for building a series array with scanning capabilities.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A novel planar radiating element that enhances signigicantly the impedance bandwidth of the microstrip radiators has been already demonstrated by the authors. This element is similar to a slot etched on the ground plane of a microstrip line, with the peculiarity of having superimposed onto it its complementary stub. This paper reviews the main characteristics of the complementary strip-slot element and describes its use for building a series array with scanning capabilities. |
Abdo-Sánchez, E; Esteban, J; Martín-Guerrero, T M; Page, J E; Camacho-Peñalosa, C Microstrip series-fed array based on the strip-slot element Artículo en actas Proceedings of the 7th European Conference on Antennas and Propagation (EuCAP), pp. 1447-1450, Gothenburg (Sweden), 2013, (ISBN: 978-1-4673-2187-7). @inproceedings{AbdoSanchez2013b, title = {Microstrip series-fed array based on the strip-slot element}, author = {E Abdo-Sánchez and J Esteban and T M Martín-Guerrero and J E Page and C Camacho-Peñalosa}, year = {2013}, date = {2013-04-01}, booktitle = {Proceedings of the 7th European Conference on Antennas and Propagation (EuCAP)}, pages = {1447-1450}, address = {Gothenburg (Sweden)}, abstract = {A novel series array, based on the use of the broadband complementary strip-slot radiating element loading a microstrip line, is presented. The main advantage of this proposal is that, by using this broadly-matched slot radiator, the design of such a slot planar array is simplified, since it is not required to make any effort to match the structure. An array with five elements has been manufactured and measurements of the reflection response are presented. In addition, the scanning capabilities of the array are analysed by applying the spatial harmonic expansion and proven by electromagnetic simulations. The proposed structure is able to scan from backward to forward beam directions within two radiating bands (around 6.3GHz and 14.1GHz).}, note = {ISBN: 978-1-4673-2187-7}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A novel series array, based on the use of the broadband complementary strip-slot radiating element loading a microstrip line, is presented. The main advantage of this proposal is that, by using this broadly-matched slot radiator, the design of such a slot planar array is simplified, since it is not required to make any effort to match the structure. An array with five elements has been manufactured and measurements of the reflection response are presented. In addition, the scanning capabilities of the array are analysed by applying the spatial harmonic expansion and proven by electromagnetic simulations. The proposed structure is able to scan from backward to forward beam directions within two radiating bands (around 6.3GHz and 14.1GHz). |
Perez-Palomino, Gerardo; Baine, Paul; Dickie, Raymond; Bain, Michael; Encinar, Jose A; Cahill, Robert; Barba, Mariano; Toso, Giovanni Design and Experimental Validation of Liquid Crystal-Based Reconfigurable Reflectarray Elements With Improved Bandwidth in F-Band Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (4, 1, SI), pp. 1704-1713, 2013, ISSN: 0018-926X. @article{PerezPalomino2013, title = {Design and Experimental Validation of Liquid Crystal-Based Reconfigurable Reflectarray Elements With Improved Bandwidth in F-Band}, author = {Gerardo Perez-Palomino and Paul Baine and Raymond Dickie and Michael Bain and Jose A Encinar and Robert Cahill and Mariano Barba and Giovanni Toso}, doi = {10.1109/TAP.2013.2242833}, issn = {0018-926X}, year = {2013}, date = {2013-04-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {61}, number = {4, 1, SI}, pages = {1704-1713}, abstract = {A reconfigurable reflectarray which exploits the dielectric anisotropy of liquid crystals (LC) has been designed to operate in the frequency range from 96 to 104 GHz. The unit cells are composed of three unequal length parallel dipoles placed above an LC substrate. The reflectarray has been designed using an accurate model which includes the effects of anisotropy and inhomogeneity. An effective permittivity that accounts for the `real effects' of the LC has also been used to simplify the analysis and design of the unit cells. The geometrical parameters of the cells have been adjusted to simultaneously improve the bandwidth, maximize the tunable phase-range and reduce the sensitivity to the angle of incidence. The performance of the LC based unit cells has been experimentally evaluated by measuring the reflection amplitude and phase of a reflectarray consisting of 52 x 54 identical cells. The good agreement between measurements and simulations validates the analysis and design techniques and demonstrates the capabilities of the proposed reflectarray to provide beam scanning in F band.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A reconfigurable reflectarray which exploits the dielectric anisotropy of liquid crystals (LC) has been designed to operate in the frequency range from 96 to 104 GHz. The unit cells are composed of three unequal length parallel dipoles placed above an LC substrate. The reflectarray has been designed using an accurate model which includes the effects of anisotropy and inhomogeneity. An effective permittivity that accounts for the `real effects' of the LC has also been used to simplify the analysis and design of the unit cells. The geometrical parameters of the cells have been adjusted to simultaneously improve the bandwidth, maximize the tunable phase-range and reduce the sensitivity to the angle of incidence. The performance of the LC based unit cells has been experimentally evaluated by measuring the reflection amplitude and phase of a reflectarray consisting of 52 x 54 identical cells. The good agreement between measurements and simulations validates the analysis and design techniques and demonstrates the capabilities of the proposed reflectarray to provide beam scanning in F band. |
Tienda, Carolina; Encinar, Jose A; Arrebola, Manuel; Barba, Mariano; Carrasco, Eduardo Design, Manufacturing and Test of a Dual-Reflectarray Antenna With Improved Bandwidth and Reduced Cross-Polarization Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (3), pp. 1180-1190, 2013, ISSN: 0018-926X. @article{Tienda2013, title = {Design, Manufacturing and Test of a Dual-Reflectarray Antenna With Improved Bandwidth and Reduced Cross-Polarization}, author = {Carolina Tienda and Jose A Encinar and Manuel Arrebola and Mariano Barba and Eduardo Carrasco}, doi = {10.1109/TAP.2012.2228620}, issn = {0018-926X}, year = {2013}, date = {2013-03-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {61}, number = {3}, pages = {1180-1190}, abstract = {A dual-offset reflectarray demonstrator has been designed, manufactured and tested for the first time. In the antenna configuration presented in this paper, the feed, the sub-reflectarray and the main-reflectarray are in the near field one to each other, so that the conventional approximations of far field are not suitable for the analysis of this antenna. The antenna is designed by considering the near-field radiated by the horn and the contributions from all the elements in the sub-reflectarray to compute the required phase-shift on each element of the main reflectarray. Both reflectarrays have been designed using broad-band elements based on variable-size patches in a single layer for the main reflectarray and two layers for the sub-reflectarray, incident field. The measured radiation patterns are in good agreement with the simulated results. It is also demonstrated that a reduction of the cross-polarization in the antenna is achieved by adjusting the patch dimensions. The antenna measurements exhibit a 20% bandwidth (12.2 GHz-15 GHz) (with a reduction of gain less than 2.5 dB) and a cross-polar discrimination better than 30 dB in the working frequency band.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A dual-offset reflectarray demonstrator has been designed, manufactured and tested for the first time. In the antenna configuration presented in this paper, the feed, the sub-reflectarray and the main-reflectarray are in the near field one to each other, so that the conventional approximations of far field are not suitable for the analysis of this antenna. The antenna is designed by considering the near-field radiated by the horn and the contributions from all the elements in the sub-reflectarray to compute the required phase-shift on each element of the main reflectarray. Both reflectarrays have been designed using broad-band elements based on variable-size patches in a single layer for the main reflectarray and two layers for the sub-reflectarray, incident field. The measured radiation patterns are in good agreement with the simulated results. It is also demonstrated that a reduction of the cross-polarization in the antenna is achieved by adjusting the patch dimensions. The antenna measurements exhibit a 20% bandwidth (12.2 GHz-15 GHz) (with a reduction of gain less than 2.5 dB) and a cross-polar discrimination better than 30 dB in the working frequency band. |
Carrasco, Eduardo; Tamagnone, M; Perruisseau-Carrier, J Tunable graphene reflective cells for THz reflectarrays and generalized law of reflection Artículo de revista APPLIED PHYSICS LETTERS, 102 (10), 2013, ISSN: 0003-6951. @article{ISI:000316501200095, title = {Tunable graphene reflective cells for THz reflectarrays and generalized law of reflection}, author = {Eduardo Carrasco and M Tamagnone and J Perruisseau-Carrier}, doi = {10.1063/1.4795787}, issn = {0003-6951}, year = {2013}, date = {2013-03-01}, journal = {APPLIED PHYSICS LETTERS}, volume = {102}, number = {10}, abstract = {A tunable graphene-based reflective cell operating at THz is proposed for use in reconfigurable-beam reflectarrays, or similarly to implement the so-called generalized law of reflection. The change in the complex conductivity of graphene when biased by an electric field allows controlling the phase of the reflected field at each element of the array. Additionally, the slow wave propagation supported by graphene drastically reduces the dimensions of the cell, which allows smaller inter-element spacing hence better array performance. An elementary cell is optimized and its scattering parameters computed, demonstrating a dynamic phase range of 300 degrees and good loss figure for realistic chemical potential variations. Finally, a circuit model is proposed and shown to very accurately predict the element response. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795787]}, keywords = {}, pubstate = {published}, tppubtype = {article} } A tunable graphene-based reflective cell operating at THz is proposed for use in reconfigurable-beam reflectarrays, or similarly to implement the so-called generalized law of reflection. The change in the complex conductivity of graphene when biased by an electric field allows controlling the phase of the reflected field at each element of the array. Additionally, the slow wave propagation supported by graphene drastically reduces the dimensions of the cell, which allows smaller inter-element spacing hence better array performance. An elementary cell is optimized and its scattering parameters computed, demonstrating a dynamic phase range of 300 degrees and good loss figure for realistic chemical potential variations. Finally, a circuit model is proposed and shown to very accurately predict the element response. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795787] |
Page, J E; Esteban, J Dual-Band Matching Properties of the C-Section All-Pass Network Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 61 (2), pp. 827 -832, 2013, ISSN: 0018-9480. @article{Page2013, title = {Dual-Band Matching Properties of the C-Section All-Pass Network}, author = {J E Page and J Esteban}, doi = {10.1109/TMTT.2012.2231876}, issn = {0018-9480}, year = {2013}, date = {2013-02-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {61}, number = {2}, pages = {827 -832}, abstract = {The all-pass C-section is introduced as a replacement for the classic quarter-wave section in the design of wideband dual-band impedance-matching networks. First, the impedance-matching properties of the all-pass C-section are presented, showing its dual-band behavior. Second, a simple adaptation to dual-band designs of the well-known wideband designs with binomial and Chebyshev responses is introduced. Finally, a dual-band power divider is presented, as a test of the introduced design technique.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The all-pass C-section is introduced as a replacement for the classic quarter-wave section in the design of wideband dual-band impedance-matching networks. First, the impedance-matching properties of the all-pass C-section are presented, showing its dual-band behavior. Second, a simple adaptation to dual-band designs of the well-known wideband designs with binomial and Chebyshev responses is introduced. Finally, a dual-band power divider is presented, as a test of the introduced design technique. |
Leal-Sevillano, Carlos A; Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Equivalent circuit of multi-aperture waveguide irises and its application in the design of compact filters Artículo en actas 2013 USNC-URSI RADIO SCIENCE MEETING (JOINT WITH AP-S SYMPOSIUM), pp. 166, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; URSI; USNC 2013, ISSN: 2572-3804, (IEEE AP-S/URSI-USNC Symposium, Lake Buena Vista, FL, JUL 07-13, 2013). @inproceedings{LealSevillano2013f, title = {Equivalent circuit of multi-aperture waveguide irises and its application in the design of compact filters}, author = {Carlos A Leal-Sevillano and Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1109/USNC-URSI.2013.6715472}, issn = {2572-3804}, year = {2013}, date = {2013-01-01}, booktitle = {2013 USNC-URSI RADIO SCIENCE MEETING (JOINT WITH AP-S SYMPOSIUM)}, pages = {166}, organization = {Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; URSI; USNC}, series = {USNC-URSI Radio Science Meeting - Joint with AP-S SYMPOSIUM}, note = {IEEE AP-S/URSI-USNC Symposium, Lake Buena Vista, FL, JUL 07-13, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Leal-Sevillano, Carlos A; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M Dual-Band Bi-Phase Waveguide Polarizer for a Novel Feeder Network without Orthomode Transducer Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 593-596, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). @inproceedings{LealSevillano2013e, title = {Dual-Band Bi-Phase Waveguide Polarizer for a Novel Feeder Network without Orthomode Transducer}, author = {Carlos A Leal-Sevillano and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.23919/EuMC.2013.6686725}, issn = {2325-0305}, year = {2013}, date = {2013-01-01}, booktitle = {2013 EUROPEAN MICROWAVE CONFERENCE (EUMC)}, pages = {593-596}, organization = {APS}, series = {European Microwave Conference}, abstract = {Waveguide polarizers are essential devices in communication systems used as horn feeders for achieving circular polarization. In this paper a new bi-phase waveguide polarizer for working in two different frequency bands is proposed. Furthermore, the presented polarizer is the critical component of a completely new feeder network proposed herein, which does not require Orthomode Transducer. The design and full-wave optimization of the novel structure realized in rectangular waveguide is presented. The full-wave analysis is carried out with efficient Computer Aided Design (CAD) software based on the ModeMatching technique. A high performance in polarization purity is obtained in comparison with existing dual-band waveguide polarizers. The optimized design presents a return loss better than 27 dB for both polarizations (vertical and horizontal) in both bands and a phase difference of 90 degrees +/- 0.7 degrees (equivalent to an axial ratio better than 0.12 dB or a maximum cross-polar level of -45 dB).}, note = {43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Waveguide polarizers are essential devices in communication systems used as horn feeders for achieving circular polarization. In this paper a new bi-phase waveguide polarizer for working in two different frequency bands is proposed. Furthermore, the presented polarizer is the critical component of a completely new feeder network proposed herein, which does not require Orthomode Transducer. The design and full-wave optimization of the novel structure realized in rectangular waveguide is presented. The full-wave analysis is carried out with efficient Computer Aided Design (CAD) software based on the ModeMatching technique. A high performance in polarization purity is obtained in comparison with existing dual-band waveguide polarizers. The optimized design presents a return loss better than 27 dB for both polarizations (vertical and horizontal) in both bands and a phase difference of 90 degrees +/- 0.7 degrees (equivalent to an axial ratio better than 0.12 dB or a maximum cross-polar level of -45 dB). |
Leal-Sevillano, Carlos A; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M Compact Broadband Couplers Based on the Waveguide Magic-T Junction Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 151-154, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). @inproceedings{LealSevillano2013d, title = {Compact Broadband Couplers Based on the Waveguide Magic-T Junction}, author = {Carlos A Leal-Sevillano and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.23919/EuMC.2013.6686613}, issn = {2325-0305}, year = {2013}, date = {2013-01-01}, booktitle = {2013 EUROPEAN MICROWAVE CONFERENCE (EUMC)}, pages = {151-154}, organization = {APS}, series = {European Microwave Conference}, abstract = {In this paper, a broadband 180 degrees waveguide directional coupler based on a modified magic-T junction is presented. The well-known magic-T waveguide junction is effectively modified and optimized leading to enhanced performance. Moreover, the volume of the proposed enhanced magic-T is similar to the classic junction. The novel magic-T proposed uses an iris in the E port, a single width step in the H port, a simple post in the junction and reduced height in the H and common ports. The bandwidth of the directional coupler can be significantly enlarged with a proper optimization of these four key elements. Different designs are presented covering the full standard rectangular waveguide band, over 40% relative bandwidth, with more than 25 dB return loss in the four ports. In addition, a compact bend with integrated transformer is introduced at the input/output interfaces.}, note = {43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } In this paper, a broadband 180 degrees waveguide directional coupler based on a modified magic-T junction is presented. The well-known magic-T waveguide junction is effectively modified and optimized leading to enhanced performance. Moreover, the volume of the proposed enhanced magic-T is similar to the classic junction. The novel magic-T proposed uses an iris in the E port, a single width step in the H port, a simple post in the junction and reduced height in the H and common ports. The bandwidth of the directional coupler can be significantly enlarged with a proper optimization of these four key elements. Different designs are presented covering the full standard rectangular waveguide band, over 40% relative bandwidth, with more than 25 dB return loss in the four ports. In addition, a compact bend with integrated transformer is introduced at the input/output interfaces. |
Garcia, Jesus; Rubio, Jesús; Gil, Jose M; Gonzalez-de-Aza, Miguel A; de la Rubia, Valentín; Zapata, Juan Spherical Modes in Computational Electromagnetics applied to Antenna Problems Artículo en actas Dénia, Spain, 2013. @inproceedings{Garcia2013, title = {Spherical Modes in Computational Electromagnetics applied to Antenna Problems}, author = {Jesus Garcia and Jesús Rubio and Jose M Gil and Miguel A Gonzalez-de-Aza and Valentín de la Rubia and Juan Zapata}, year = {2013}, date = {2013-01-01}, address = {Dénia, Spain}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Jaafari, Bilal El; Garcia, Jesus; Rubio, Jesús; Gil, Jose M; Gonzalez-de-Aza, Miguel A; de la Rubia, Valentín; Zapata, Juan Fast and accurate design tools for microwave filters via domain decomposition in FEM and reduced-order models Artículo en actas Dénia, Spain, 2013. @inproceedings{Jaafari2013, title = {Fast and accurate design tools for microwave filters via domain decomposition in FEM and reduced-order models}, author = {Bilal El Jaafari and Jesus Garcia and Jesús Rubio and Jose M Gil and Miguel A Gonzalez-de-Aza and Valentín de la Rubia and Juan Zapata}, year = {2013}, date = {2013-01-01}, address = {Dénia, Spain}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
de la Rubia, Valentin; Rubio, Jesus; Gil, Jose M; Zapata, Juan Fast and Reliable Monostatic RCS Computation as a Function of Frequency and Angle of Observation via the Reduced-Basis Method Artículo en actas Orlando, Florida, USA, 2013. @inproceedings{Rubia2013, title = {Fast and Reliable Monostatic RCS Computation as a Function of Frequency and Angle of Observation via the Reduced-Basis Method}, author = {Valentin de la Rubia and Jesus Rubio and Jose M Gil and Juan Zapata}, year = {2013}, date = {2013-01-01}, address = {Orlando, Florida, USA}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Navarro-Tapia, M; Esteban, J; Camacho-Peñalosa, C Broadband slot array antenna with full-space steerable pattern in a composite right/left-handed waveguide Artículo de revista Radio Science, 48 (4), pp. 406-415, 2013. @article{NavarroTapia2013, title = {Broadband slot array antenna with full-space steerable pattern in a composite right/left-handed waveguide}, author = {M Navarro-Tapia and J Esteban and C Camacho-Peñalosa}, doi = {10.1002/rds.20046}, year = {2013}, date = {2013-01-01}, journal = {Radio Science}, volume = {48}, number = {4}, pages = {406-415}, abstract = {The aim of this paper is twofold. On the one hand, to provide a better understanding of a composite right/left-handed (CRLH) waveguide, going into those aspects of interest for an antenna designer. A longitudinal slot as a radiating element has been considered to be studied and compared with its classic counterpart. On the other hand, to present the new design approach that is needed when using the CRLH waveguide technology to built array antennas. To that end, a slot array antenna has been designed, built, and measured. The simulations and measurements are in excellent agreement, confirming not only the backward-to-forward beam steering and broadband far-field performance, but also the validity of the design procedure used.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aim of this paper is twofold. On the one hand, to provide a better understanding of a composite right/left-handed (CRLH) waveguide, going into those aspects of interest for an antenna designer. A longitudinal slot as a radiating element has been considered to be studied and compared with its classic counterpart. On the other hand, to present the new design approach that is needed when using the CRLH waveguide technology to built array antennas. To that end, a slot array antenna has been designed, built, and measured. The simulations and measurements are in excellent agreement, confirming not only the backward-to-forward beam steering and broadband far-field performance, but also the validity of the design procedure used. |
Abdo-Sánchez, E; Esteban, J; Martín-Guerrero, T M; Page, J E; Camacho-Peñalosa, C The use of lattice networks for modelling symmetric transmission line components and discontinuities Artículo de revista Microwave and Optical Technology Letters, 55 (3), pp. 636-639, 2013. @article{AbdoSanchez2013, title = {The use of lattice networks for modelling symmetric transmission line components and discontinuities}, author = {E Abdo-Sánchez and J Esteban and T M Martín-Guerrero and J E Page and C Camacho-Peñalosa}, doi = {10.1002/mop.27385}, year = {2013}, date = {2013-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {55}, number = {3}, pages = {636-639}, abstract = {This article proposes the lattice network as a beneficial alternative to T- and Pi-topologies for modeling symmetric transmission line discontinuities and components.The lattice network presents some important features, which make it a powerful tool to find realizable equivalent circuits. The limitations of the T- and Pi-topologies and the validity of the lattice network in terms of realizability are highlighted in this article through two microstrip components: a dumbbell-shaped defected ground structure and a microstrip stepped-impedance hairpin resonator. Moreover, the lattice image impedance is proposed here as a parameter that allows determining whether a branch of the network is predominant.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article proposes the lattice network as a beneficial alternative to T- and Pi-topologies for modeling symmetric transmission line discontinuities and components.The lattice network presents some important features, which make it a powerful tool to find realizable equivalent circuits. The limitations of the T- and Pi-topologies and the validity of the lattice network in terms of realizability are highlighted in this article through two microstrip components: a dumbbell-shaped defected ground structure and a microstrip stepped-impedance hairpin resonator. Moreover, the lattice image impedance is proposed here as a parameter that allows determining whether a branch of the network is predominant. |
Doumanis, E; Dickie, Raymond; Baine, Paul; Perez-Palomino, Gerardo; Cahill, Robert; Goussetis, G; Encinar, Jose A; Barba, Mariano; Christie, S; Mitchell, N; Bain, Michael; Toso, Giovanni Nematic Liquid Crystals for Reconfigurable Millimeter Wavelength Antenna Technology Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1791+, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). @inproceedings{Doumanis2013, title = {Nematic Liquid Crystals for Reconfigurable Millimeter Wavelength Antenna Technology}, author = {E Doumanis and Raymond Dickie and Paul Baine and Gerardo Perez-Palomino and Robert Cahill and G Goussetis and Jose A Encinar and Mariano Barba and S Christie and N Mitchell and Michael Bain and Giovanni Toso}, issn = {2164-3342}, year = {2013}, date = {2013-01-01}, booktitle = {2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, pages = {1791+}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {Nematic liquid crystals (LC) offer the capability to electronically reconfigure their dielectric permittivity tensor by applying a low AC voltage. This feature can find pertinent applications in submm-wave antenna technology in developing reconfigurable devices. In this contribution we review recent developments for the dielectric characterization of nematic liquid crystal samples at mm wavelengths and describe their applications in reconfigurable reflectarray antenna and tunable linear to circular polarization reflectors. The paper describes the theoretical aspects which underpin the technology that is employed for the realization, packaging and testing.}, note = {7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Nematic liquid crystals (LC) offer the capability to electronically reconfigure their dielectric permittivity tensor by applying a low AC voltage. This feature can find pertinent applications in submm-wave antenna technology in developing reconfigurable devices. In this contribution we review recent developments for the dielectric characterization of nematic liquid crystal samples at mm wavelengths and describe their applications in reconfigurable reflectarray antenna and tunable linear to circular polarization reflectors. The paper describes the theoretical aspects which underpin the technology that is employed for the realization, packaging and testing. |
Florencio, Rafael; Boix, Rafael R; Encinar, Jose A Improvements in the MoM Analysis of 2-D Planar Multilayered Periodic Structures Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 612+, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). @inproceedings{Florencio2013c, title = {Improvements in the MoM Analysis of 2-D Planar Multilayered Periodic Structures}, author = {Rafael Florencio and Rafael R Boix and Jose A Encinar}, issn = {2164-3342}, year = {2013}, date = {2013-01-01}, booktitle = {2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, pages = {612+}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {In this paper the authors apply the Method of Moments (MoM) to the analysis of the scattering of a multilayered periodic strip grating by a plane wave with oblique incidence and arbitrary polarization. It is shown that the use of an improved MoM spatial domain approach is one order of magnitude faster than the use of the classical MoM spectral domain approach when basis functions that account for edge singularities are used in the modeling of the current density on the metallizations.}, note = {7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } In this paper the authors apply the Method of Moments (MoM) to the analysis of the scattering of a multilayered periodic strip grating by a plane wave with oblique incidence and arbitrary polarization. It is shown that the use of an improved MoM spatial domain approach is one order of magnitude faster than the use of the classical MoM spectral domain approach when basis functions that account for edge singularities are used in the modeling of the current density on the metallizations. |
Encinar, Jose A; Tienda, Carolina; Barba, Mariano; Carrasco, Eduardo; Arrebola, Manuel Analysis, Design and Prototyping of Reflectarray Antennas for Space Applications Artículo en actas {Edwards, RM} (Ed.): 2013 LOUGHBOROUGH ANTENNAS AND PROPAGATION CONFERENCE (LAPC), pp. 1-5, 2013, ISBN: 978-1-4799-0091-6, (Loughborough Antennas and Propagation Conference (LAPC), Loughborough Univ, Loughborough, ENGLAND, NOV 11-12, 2013). @inproceedings{Encinar2013, title = {Analysis, Design and Prototyping of Reflectarray Antennas for Space Applications}, author = {Jose A Encinar and Carolina Tienda and Mariano Barba and Eduardo Carrasco and Manuel Arrebola}, editor = {RM} {Edwards}, isbn = {978-1-4799-0091-6}, year = {2013}, date = {2013-01-01}, booktitle = {2013 LOUGHBOROUGH ANTENNAS AND PROPAGATION CONFERENCE (LAPC)}, pages = {1-5}, abstract = {This work presents the recent developments of reflectarray antennas for space applications carried out by Universidad Politecnica de Madrid, which includes analysis and design techniques for single and dual reflector configurations, design procedures for contoured beams and bandwidth improvement and some practical realizations. Several reflectarray demonstrators are described for Direct Broadcast Satellite (DBS), multi-beam antennas and reconfigurable-beam reflectarrays.}, note = {Loughborough Antennas and Propagation Conference (LAPC), Loughborough Univ, Loughborough, ENGLAND, NOV 11-12, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This work presents the recent developments of reflectarray antennas for space applications carried out by Universidad Politecnica de Madrid, which includes analysis and design techniques for single and dual reflector configurations, design procedures for contoured beams and bandwidth improvement and some practical realizations. Several reflectarray demonstrators are described for Direct Broadcast Satellite (DBS), multi-beam antennas and reconfigurable-beam reflectarrays. |
Perez-Palomino, Gerardo; Encinar, Jose A; Dickie, Raymond; Cahill, Robert Preliminary Design of a Liquid Crystal-Based Reflectarray Antenna for Beam-Scanning in THz Artículo en actas 2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 2277+, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS 2013, ISSN: 1522-3965, (International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013). @inproceedings{PerezPalomino2013a, title = {Preliminary Design of a Liquid Crystal-Based Reflectarray Antenna for Beam-Scanning in THz}, author = {Gerardo Perez-Palomino and Jose A Encinar and Raymond Dickie and Robert Cahill}, issn = {1522-3965}, year = {2013}, date = {2013-01-01}, booktitle = {2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI)}, pages = {2277+}, organization = {Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS}, series = {IEEE Antennas and Propagation Society International Symposium}, abstract = {A 50.22 x 48.6 mm beam-scanning reflectarray based on liquid crystals (LCs) has been designed to operate over a bandwidth of 5.5% in the low THz frequency range. The structure consists of a single-layer multi-resonant periodic array with unit- cells composed of three parallel unequal length dipoles. The gap between the array and ground plane is filled with electronically tunable LC which exhibits a permittivity value that is controlled by a low frequency bias signal. The simulations demonstrate that the beam can be scanned over an angular range of +/- 10 degrees yielding a gain greater than 35 dBi and maximum sidelobe levels of 25 dB from 335 to 354 GHz.}, note = {International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A 50.22 x 48.6 mm beam-scanning reflectarray based on liquid crystals (LCs) has been designed to operate over a bandwidth of 5.5% in the low THz frequency range. The structure consists of a single-layer multi-resonant periodic array with unit- cells composed of three parallel unequal length dipoles. The gap between the array and ground plane is filled with electronically tunable LC which exhibits a permittivity value that is controlled by a low frequency bias signal. The simulations demonstrate that the beam can be scanned over an angular range of +/- 10 degrees yielding a gain greater than 35 dBi and maximum sidelobe levels of 25 dB from 335 to 354 GHz. |
Florencio, Rafael; Boix, Rafael R; Encinar, Jose A Design of a Reflectarray Antenna at 300 GHz Based on Cells with Three Coplanar Dipoles Artículo en actas 2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 1350+, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS 2013, ISSN: 1522-3965, (International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013). @inproceedings{Florencio2013b, title = {Design of a Reflectarray Antenna at 300 GHz Based on Cells with Three Coplanar Dipoles}, author = {Rafael Florencio and Rafael R Boix and Jose A Encinar}, issn = {1522-3965}, year = {2013}, date = {2013-01-01}, booktitle = {2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI)}, pages = {1350+}, organization = {Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS}, series = {IEEE Antennas and Propagation Society International Symposium}, abstract = {Simulated results are presented for a reflectarray antenna designed to produce a collimated beam at 300 GHz within a 13% bandwidth. The reflectarray cells are made of three parallel dipoles printed on one side of a 110-mu m Quartz wafer coated with a conductive ground plane on the back side, where the phase is adjusted by varying the length of the dipoles. A practically linear phase variation is achieved in a range greater than 360 degrees and frequencies from 280 GHz to 320 GHz. A reflectarray antenna was designed taking into account the angle of incidence and the polarization of the incident field. The simulated radiation patterns show a fixed collimated beam with variations in gain lower than 2.6 dB within a 13% bandwidth.}, note = {International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Simulated results are presented for a reflectarray antenna designed to produce a collimated beam at 300 GHz within a 13% bandwidth. The reflectarray cells are made of three parallel dipoles printed on one side of a 110-mu m Quartz wafer coated with a conductive ground plane on the back side, where the phase is adjusted by varying the length of the dipoles. A practically linear phase variation is achieved in a range greater than 360 degrees and frequencies from 280 GHz to 320 GHz. A reflectarray antenna was designed taking into account the angle of incidence and the polarization of the incident field. The simulated radiation patterns show a fixed collimated beam with variations in gain lower than 2.6 dB within a 13% bandwidth. |
van't Klooster, C G M; Pacheco, A; Montesano, Carlos E; Encinar, Jose A; Culebras, A Reflect-Array Sub-Reflector in X-Ka Band Antenna Artículo en actas 2013 PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP), VOLS 1 AND 2, SE Univ; Univ Elect Sci & Technol China; CIE Antenna Soc; IEICE Commun Soc; IEEE Antennas & Propagat Soc; European Assoc Antennas & Propagat; Sci & Technol Antenna & Microwave Lab; Jiangsu Inst Elect; IEEE AP MTT EMC Nanjing Joint Chapter; Agilent Technologies; FEKO; Mitsubishi Elect; Bluetest se; Journal Microwaves; MMW 2013, ISBN: 978-7-5641-4279-7, (International Symposium on Antennas and Propagation (ISAP), Nanjing, PEOPLES R CHINA, OCT 23-25, 2013). @inproceedings{Klooster2013, title = {Reflect-Array Sub-Reflector in X-Ka Band Antenna}, author = {C G M van't Klooster and A Pacheco and Carlos E Montesano and Jose A Encinar and A Culebras}, isbn = {978-7-5641-4279-7}, year = {2013}, date = {2013-01-01}, booktitle = {2013 PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP), VOLS 1 AND 2}, organization = {SE Univ; Univ Elect Sci & Technol China; CIE Antenna Soc; IEICE Commun Soc; IEEE Antennas & Propagat Soc; European Assoc Antennas & Propagat; Sci & Technol Antenna & Microwave Lab; Jiangsu Inst Elect; IEEE AP MTT EMC Nanjing Joint Chapter; Agilent Technologies; FEKO; Mitsubishi Elect; Bluetest se; Journal Microwaves; MMW}, abstract = {An X-Ka band high gain antenna configuration is discussed in which the gain is improved by using a reflect-array on the sub-reflector. The implementation is for a dual reflector antenna with a dual frequency feed. Experiences in Spanish institutions have been combined, like reflect-array developments (UPM), feed design and technology (Rymsa) and design and technological manufacturing processes (EADS CASA Espacio). Control of reflection properties (specific design of reflect-array) assists to obtain good performances for an antenna configuration. It allows making efficient use of the antenna aperture for two different bands for high-gain, whilst controlling separate bands.}, note = {International Symposium on Antennas and Propagation (ISAP), Nanjing, PEOPLES R CHINA, OCT 23-25, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } An X-Ka band high gain antenna configuration is discussed in which the gain is improved by using a reflect-array on the sub-reflector. The implementation is for a dual reflector antenna with a dual frequency feed. Experiences in Spanish institutions have been combined, like reflect-array developments (UPM), feed design and technology (Rymsa) and design and technological manufacturing processes (EADS CASA Espacio). Control of reflection properties (specific design of reflect-array) assists to obtain good performances for an antenna configuration. It allows making efficient use of the antenna aperture for two different bands for high-gain, whilst controlling separate bands. |
Carrasco, Eduardo; Perruisseau-Carrier, J Reflectarray Antenna at Terahertz Using Graphene Artículo de revista IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, 12 , pp. 253-256, 2013, ISSN: 1536-1225. @article{ISI:000316465200007, title = {Reflectarray Antenna at Terahertz Using Graphene}, author = {Eduardo Carrasco and J Perruisseau-Carrier}, doi = {10.1109/LAWP.2013.2247557}, issn = {1536-1225}, year = {2013}, date = {2013-01-01}, journal = {IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS}, volume = {12}, pages = {253-256}, abstract = {The use of graphene for fixed-beam reflectarray antennas at Terahertz (THz) is proposed. Graphene's unique electronic band structure leads to a complex surface conductivity at THz frequencies, which allows the propagation of very slow plasmonic modes. This leads to a drastic reduction of the electrical size of the array unit cell and thereby good array performance. The proposed reflectarray has been designed at 1.3 THz and comprises more than 25 000 elements of size about lambda(0)/16. The array reflective unit cell is analyzed using a full vectorial approach, taking into account the variation of the angle of incidence and assuming local periodicity. Good performance is obtained in terms of bandwidth, cross-polar, and grating lobes suppression, proving the feasibility of graphene-based reflectarrays and other similar spatially fed structures at Terahertz frequencies. This result is also a first important step toward reconfigurable THz reflectarrays using graphene electric field effect.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The use of graphene for fixed-beam reflectarray antennas at Terahertz (THz) is proposed. Graphene's unique electronic band structure leads to a complex surface conductivity at THz frequencies, which allows the propagation of very slow plasmonic modes. This leads to a drastic reduction of the electrical size of the array unit cell and thereby good array performance. The proposed reflectarray has been designed at 1.3 THz and comprises more than 25 000 elements of size about lambda(0)/16. The array reflective unit cell is analyzed using a full vectorial approach, taking into account the variation of the angle of incidence and assuming local periodicity. Good performance is obtained in terms of bandwidth, cross-polar, and grating lobes suppression, proving the feasibility of graphene-based reflectarrays and other similar spatially fed structures at Terahertz frequencies. This result is also a first important step toward reconfigurable THz reflectarrays using graphene electric field effect. |
Perruisseau-Carrier, J; Fallahi, A; Carrasco, Eduardo Periodic and Quasi-Periodic Graphene-Based Reconfigurable Surfaces Artículo en actas PROCEEDINGS OF 2013 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS), pp. 1070-1073, Int Union Radio Sci; Inst Elect, Informat & Commun Engineers, Elect Soc 2013, ISSN: 2163-405X, (URSI International Symposium on Electromagnetic Theory (EMTS), Int Union Radio Sci Japanese Comm, Commiss B, Hiroshima, JAPAN, MAY 20-24, 2013). @inproceedings{ISI:000327180500275, title = {Periodic and Quasi-Periodic Graphene-Based Reconfigurable Surfaces}, author = {J Perruisseau-Carrier and A Fallahi and Eduardo Carrasco}, issn = {2163-405X}, year = {2013}, date = {2013-01-01}, booktitle = {PROCEEDINGS OF 2013 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS)}, pages = {1070-1073}, organization = {Int Union Radio Sci; Inst Elect, Informat & Commun Engineers, Elect Soc}, series = {URSI International Symposium on Electromagnetic Theory}, abstract = {We present recent results related to the modelling, design, and application of graphene surfaces. Mono and multilayer graphene surfaces are patterned in a periodic or quasi-periodic manner to tailor their electromagnetic response in terms of magnitude, phase, or polarization. Applications such as frequency-selective surfaces, polarizers, Faraday rotators, beam-deflectors, and reflectarrays are considered. The structures are analyzed by studying their unit cell response in a period Floquet's environment, using both a commercial and an in-house code, only the latter being able to handle the general graphene dyadic surface conductivity tensor. Due to the significant loss of graphene at microwave frequency, most examples are related to THz frequencies and above.}, note = {URSI International Symposium on Electromagnetic Theory (EMTS), Int Union Radio Sci Japanese Comm, Commiss B, Hiroshima, JAPAN, MAY 20-24, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } We present recent results related to the modelling, design, and application of graphene surfaces. Mono and multilayer graphene surfaces are patterned in a periodic or quasi-periodic manner to tailor their electromagnetic response in terms of magnitude, phase, or polarization. Applications such as frequency-selective surfaces, polarizers, Faraday rotators, beam-deflectors, and reflectarrays are considered. The structures are analyzed by studying their unit cell response in a period Floquet's environment, using both a commercial and an in-house code, only the latter being able to handle the general graphene dyadic surface conductivity tensor. Due to the significant loss of graphene at microwave frequency, most examples are related to THz frequencies and above. |
Carrasco, Eduardo; Tamagnone, M; Perruisseau-Carrier, J Tunable Graphene-Based Reflectarray Element for Reconfigurable Beams Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1779-1782, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). @inproceedings{ISI:000327126001159, title = {Tunable Graphene-Based Reflectarray Element for Reconfigurable Beams}, author = {Eduardo Carrasco and M Tamagnone and J Perruisseau-Carrier}, issn = {2164-3342}, year = {2013}, date = {2013-01-01}, booktitle = {2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, pages = {1779-1782}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {Tunable reflective elements based on graphene patches are proposed for reconfigurable-beam reflectarray antennas. The complex conductivity of graphene can be dynamically varied when an electric field is applied, allowing to control the phase of the reflected wave at each element of the reflectarray. The proposed patches support plasmonic slow wave propagation at THz frequencies, drastically reducing the physical dimensions of the cell. Here, an element which provides a dynamic phase range of more than 300 degrees is demonstrated with moderate losses in a wide band. The scattering matrix of the element has been obtained by full-wave electromagnetic simulations and also by a circuit approach accurately modeling the graphene cell response.}, note = {7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Tunable reflective elements based on graphene patches are proposed for reconfigurable-beam reflectarray antennas. The complex conductivity of graphene can be dynamically varied when an electric field is applied, allowing to control the phase of the reflected wave at each element of the reflectarray. The proposed patches support plasmonic slow wave propagation at THz frequencies, drastically reducing the physical dimensions of the cell. Here, an element which provides a dynamic phase range of more than 300 degrees is demonstrated with moderate losses in a wide band. The scattering matrix of the element has been obtained by full-wave electromagnetic simulations and also by a circuit approach accurately modeling the graphene cell response. |
Perruisseau-Carrier, J; Tamagnone, M; Gomez-Diaz, Juan Sebastian; Carrasco, Eduardo Graphene Antennas: Can Integration and Reconfigurability Compensate for the Loss? Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 369-372, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). @inproceedings{ISI:000330768700094, title = {Graphene Antennas: Can Integration and Reconfigurability Compensate for the Loss?}, author = {J Perruisseau-Carrier and M Tamagnone and Juan Sebastian Gomez-Diaz and Eduardo Carrasco}, issn = {2325-0305}, year = {2013}, date = {2013-01-01}, booktitle = {2013 EUROPEAN MICROWAVE CONFERENCE (EUMC)}, pages = {369-372}, organization = {APS}, series = {European Microwave Conference}, abstract = {In this opening presentation we will first recall the main characteristics of graphene conductivity and electromagnetic wave propagation on graphene-based structures. Based on these observations and different graphene antenna simulations from microwave to terahertz, we will discuss the issue of antenna efficiency, integration and reconfigurability, as function of the operation frequency range. While the use of graphene for antennas at microwave appears extremely limited, the plasmonic nature of graphene conductivity at terahertz frequency allows unprecedented antenna properties and in particular efficient dynamic reconfiguration.}, note = {43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } In this opening presentation we will first recall the main characteristics of graphene conductivity and electromagnetic wave propagation on graphene-based structures. Based on these observations and different graphene antenna simulations from microwave to terahertz, we will discuss the issue of antenna efficiency, integration and reconfigurability, as function of the operation frequency range. While the use of graphene for antennas at microwave appears extremely limited, the plasmonic nature of graphene conductivity at terahertz frequency allows unprecedented antenna properties and in particular efficient dynamic reconfiguration. |
2012 |
Abdo-Sánchez, E; Page, J E; Martín-Guerrero, T M; Esteban, J; Camacho-Peñalosa, C Planar Broadband Slot Radiating Element Based on Microstrip-Slot Coupling for Series-fed Arrays Artículo de revista IEEE Transactions on Antennas and Propagation, 60 (12), pp. 6037-6042, 2012, ISSN: 0018-926X. @article{AbdoSanchez2012, title = {Planar Broadband Slot Radiating Element Based on Microstrip-Slot Coupling for Series-fed Arrays}, author = {E Abdo-Sánchez and J E Page and T M Martín-Guerrero and J Esteban and C Camacho-Peñalosa}, doi = {10.1109/TAP.2012.2211558}, issn = {0018-926X}, year = {2012}, date = {2012-12-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {60}, number = {12}, pages = {6037-6042}, abstract = {A novel planar slot radiating element with applications in series-fed arrays and significant bandwidth enhancement is presented in this communication. The structure is based on the microstrip-slotline coupling and simply consists of a microstrip-fed slot with a symmetrically-arranged strip conductor superimposed onto it. The broad impedance bandwidth (up to 16 GHz) lies in the resulting all-pass section that the strip and the slot make up. A theoretical study of the structure in terms of even and odd modes as well as a straightforward equivalent circuit are provided, which offer the required analytical tools to state the design methodology. Experimental and simulated results corroborate that the strip acts as a mere matching element that does not practically alter the slot radiation characteristics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel planar slot radiating element with applications in series-fed arrays and significant bandwidth enhancement is presented in this communication. The structure is based on the microstrip-slotline coupling and simply consists of a microstrip-fed slot with a symmetrically-arranged strip conductor superimposed onto it. The broad impedance bandwidth (up to 16 GHz) lies in the resulting all-pass section that the strip and the slot make up. A theoretical study of the structure in terms of even and odd modes as well as a straightforward equivalent circuit are provided, which offer the required analytical tools to state the design methodology. Experimental and simulated results corroborate that the strip acts as a mere matching element that does not practically alter the slot radiation characteristics. |
Carrasco, Eduardo; Barba, Mariano; Encinar, Jose A X-Band Reflectarray Antenna With Switching-Beam Using PIN Diodes and Gathered Elements Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (12), pp. 5700-5708, 2012, ISSN: 0018-926X. @article{Carrasco2012a, title = {X-Band Reflectarray Antenna With Switching-Beam Using PIN Diodes and Gathered Elements}, author = {Eduardo Carrasco and Mariano Barba and Jose A Encinar}, doi = {10.1109/TAP.2012.2208612}, issn = {0018-926X}, year = {2012}, date = {2012-12-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {60}, number = {12}, pages = {5700-5708}, abstract = {An electronically switching-beam reflectarray antenna to be used in X-band has been designed, manufactured and tested, using PIN diodes as switching device. The antenna has 244 elements arranged in a circular aperture. With the aim of saving electronic devices and reducing both manufacturing complexity and cost, the phase control has been implemented at sub-array level, using aperture-coupled patches gathered by pairs to a common delay line. The antenna was designed to switch the beam between +/- 5 degrees, in a scanning plane tilted 18.3 degrees with respect to the YZ plane. Each state was obtained by forward biasing one half of the diodes, while the other half remains in reverse biasing. A third state with the beam pointing to 0 degrees was obtained when all the diodes are in reverse biasing. The concept has been demonstrated by manufacturing and testing a breadboard. The measured radiation patterns fulfill the design requirements.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An electronically switching-beam reflectarray antenna to be used in X-band has been designed, manufactured and tested, using PIN diodes as switching device. The antenna has 244 elements arranged in a circular aperture. With the aim of saving electronic devices and reducing both manufacturing complexity and cost, the phase control has been implemented at sub-array level, using aperture-coupled patches gathered by pairs to a common delay line. The antenna was designed to switch the beam between +/- 5 degrees, in a scanning plane tilted 18.3 degrees with respect to the YZ plane. Each state was obtained by forward biasing one half of the diodes, while the other half remains in reverse biasing. A third state with the beam pointing to 0 degrees was obtained when all the diodes are in reverse biasing. The concept has been demonstrated by manufacturing and testing a breadboard. The measured radiation patterns fulfill the design requirements. |
Corcoles, Juan; Gonzalez-de-Aza, Miguel A Efficient Combined Array Thinning and Weighting for Pattern Synthesis With a Nested Optimization Scheme Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (11), pp. 5107-5117, 2012, ISSN: 0018-926X. @article{Corcoles2012, title = {Efficient Combined Array Thinning and Weighting for Pattern Synthesis With a Nested Optimization Scheme}, author = {Juan Corcoles and Miguel A Gonzalez-de-Aza}, doi = {10.1109/TAP.2012.2207667}, issn = {0018-926X}, year = {2012}, date = {2012-11-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {60}, number = {11}, pages = {5107-5117}, abstract = {A novel procedure to thin an antenna array which synthesizes a desired pattern with the minimum number of active elements is introduced. The proposed method yields both the active elements and their corresponding excitations of a thinned array having the minimum number of active elements needed to meet several prescribed design specifications of the radiated far-field pattern. Specifications such as achieving a minimum gain, obtaining a pattern with a maximum allowable sidelobe level or synthesizing a shaped beam pattern confined into a mask are considered. Null field directions can also be added. In order to carry out the thinning, a genetic algorithm is used, while computing the excitations is carried out through linear or quadratic programming. The procedure incorporates the generalized scattering matrix analysis of an array made up of elements whose radiated field can be expressed as a spherical mode expansion, thus taking all electromagnetic effects inherently into account. Therefore, since the presence of an element can substantially alter the array features because of mutual coupling, two types of thinning are considered: removing elements or turning them off. Numerical results of arrays made up of isotropic sources, dielectric resonator antennas and microstrip patch antennas are presented.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel procedure to thin an antenna array which synthesizes a desired pattern with the minimum number of active elements is introduced. The proposed method yields both the active elements and their corresponding excitations of a thinned array having the minimum number of active elements needed to meet several prescribed design specifications of the radiated far-field pattern. Specifications such as achieving a minimum gain, obtaining a pattern with a maximum allowable sidelobe level or synthesizing a shaped beam pattern confined into a mask are considered. Null field directions can also be added. In order to carry out the thinning, a genetic algorithm is used, while computing the excitations is carried out through linear or quadratic programming. The procedure incorporates the generalized scattering matrix analysis of an array made up of elements whose radiated field can be expressed as a spherical mode expansion, thus taking all electromagnetic effects inherently into account. Therefore, since the presence of an element can substantially alter the array features because of mutual coupling, two types of thinning are considered: removing elements or turning them off. Numerical results of arrays made up of isotropic sources, dielectric resonator antennas and microstrip patch antennas are presented. |
Tienda, Carolina; Encinar, Jose A; Barba, Mariano; Arrebola, Manuel Reduction of cross-polarization in offset reflectarrays using two layers of varying-sized patches Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 54 (11), pp. 2449-2454, 2012, ISSN: 0895-2477. @article{Tienda2012, title = {Reduction of cross-polarization in offset reflectarrays using two layers of varying-sized patches}, author = {Carolina Tienda and Jose A Encinar and Mariano Barba and Manuel Arrebola}, doi = {10.1002/mop.27106}, issn = {0895-2477}, year = {2012}, date = {2012-11-01}, journal = {MICROWAVE AND OPTICAL TECHNOLOGY LETTERS}, volume = {54}, number = {11}, pages = {2449-2454}, abstract = {An offset-fed reflectarray demonstrator with reduced cross-polarization has been designed, manufactured, and tested.It is demonstrated that the cross-polarization is significantly reduced by using two layers of varying-sized patches and adjusting the patch dimensions not only to shape the beam in dual-linear polarization but also to produce a cancellation of the cross-polarized reflected field in those zones in which the maximum cross-polarization is produced. The proposed technique provides a reduction better than 5 dB in the cross-polarization for both linear polarizations. The measured radiation patterns are in good agreement with the theoretical predictions, and show a cross-polar discrimination better than 30 dB in the 12.97-14.25 GHz frequency band. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2449-2454, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27106}, keywords = {}, pubstate = {published}, tppubtype = {article} } An offset-fed reflectarray demonstrator with reduced cross-polarization has been designed, manufactured, and tested.It is demonstrated that the cross-polarization is significantly reduced by using two layers of varying-sized patches and adjusting the patch dimensions not only to shape the beam in dual-linear polarization but also to produce a cancellation of the cross-polarized reflected field in those zones in which the maximum cross-polarization is produced. The proposed technique provides a reduction better than 5 dB in the cross-polarization for both linear polarizations. The measured radiation patterns are in good agreement with the theoretical predictions, and show a cross-polar discrimination better than 30 dB in the 12.97-14.25 GHz frequency band. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2449-2454, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27106 |
Leal-Sevillano, Carlos A; Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Low-Loss Elliptical Response Filter at 100 GHz Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 22 (9), pp. 459-461, 2012, ISSN: 1531-1309. @article{LealSevillano2012, title = {Low-Loss Elliptical Response Filter at 100 GHz}, author = {Carlos A Leal-Sevillano and Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1109/LMWC.2012.2212237}, issn = {1531-1309}, year = {2012}, date = {2012-09-01}, journal = {IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, volume = {22}, number = {9}, pages = {459-461}, abstract = {The design, method of fabrication and experimental validation of a pseudo-elliptical four-poles asymmetric response filter at 100 GHz with 10% of fractional bandwidth is presented. The designed filter is part of an image radar system and must fulfill stringent specifications. The proposed topology and method of fabrication improves the out of band rejection above the pass band in comparison with other classical structures, while keeping a low insertion loss level. A two-fold geometry for implementing a transmission zero is proposed, avoiding the excitation of the first higher order mode and easing the manufacturing without any tuning element. A low-cost milling process is used for the fabrication of the device. The final design fulfills the desired specifications and presents 0.6 dB of insertion loss level at 100 GHz. The excellent agreement between simulations and measurements at this frequency band in both, return loss and insertion loss, is pointed out.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The design, method of fabrication and experimental validation of a pseudo-elliptical four-poles asymmetric response filter at 100 GHz with 10% of fractional bandwidth is presented. The designed filter is part of an image radar system and must fulfill stringent specifications. The proposed topology and method of fabrication improves the out of band rejection above the pass band in comparison with other classical structures, while keeping a low insertion loss level. A two-fold geometry for implementing a transmission zero is proposed, avoiding the excitation of the first higher order mode and easing the manufacturing without any tuning element. A low-cost milling process is used for the fabrication of the device. The final design fulfills the desired specifications and presents 0.6 dB of insertion loss level at 100 GHz. The excellent agreement between simulations and measurements at this frequency band in both, return loss and insertion loss, is pointed out. |
Montejo-Garai, Jose R; Leal-Sevillano, Carlos A; Ruiz-Cruz, Jorge A; Rebollar, Jesus M; Estrada, Teresa Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis Artículo de revista FUSION ENGINEERING AND DESIGN, 87 (9), pp. 1662-1666, 2012, ISSN: 0920-3796. @article{MontejoGarai2012, title = {Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis}, author = {Jose R Montejo-Garai and Carlos A Leal-Sevillano and Jorge A Ruiz-Cruz and Jesus M Rebollar and Teresa Estrada}, doi = {10.1016/j.fusengdes.2012.06.011}, issn = {0920-3796}, year = {2012}, date = {2012-09-01}, journal = {FUSION ENGINEERING AND DESIGN}, volume = {87}, number = {9}, pages = {1662-1666}, abstract = {Band-stop or notch filters play a crucial role in plasma diagnosis systems to protect receivers from the stray radiation. In this work, a rigorous design process based on circuit synthesis in addition to an extremely compact E-plane waveguide structure is proposed for this kind of filters. On the one hand, the transfer function verifying the rejection specification is analytically obtained, fixing the minimum number of required cavities. On the other hand, a coupling structure that reduces drastically the unwanted resonances in filters with a very large pass band requirement, is presented. This coupling between the rejection cavities and the main rectangular waveguide has additional advantages: (a) unlike typical inductive irises, large coupling coefficients can be implemented (b) a pure E-plane configuration is achieved, which simplifies the manufacturing and also reduces significantly the computational effort. Experimental validation is demonstrated by two pseudo-elliptic fifth-order band-stop filters fabricated and measured in Ka and V bands. In both cases, the filters are free of spurious resonances in their total operation bands. (C) 2012 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Band-stop or notch filters play a crucial role in plasma diagnosis systems to protect receivers from the stray radiation. In this work, a rigorous design process based on circuit synthesis in addition to an extremely compact E-plane waveguide structure is proposed for this kind of filters. On the one hand, the transfer function verifying the rejection specification is analytically obtained, fixing the minimum number of required cavities. On the other hand, a coupling structure that reduces drastically the unwanted resonances in filters with a very large pass band requirement, is presented. This coupling between the rejection cavities and the main rectangular waveguide has additional advantages: (a) unlike typical inductive irises, large coupling coefficients can be implemented (b) a pure E-plane configuration is achieved, which simplifies the manufacturing and also reduces significantly the computational effort. Experimental validation is demonstrated by two pseudo-elliptic fifth-order band-stop filters fabricated and measured in Ka and V bands. In both cases, the filters are free of spurious resonances in their total operation bands. (C) 2012 Elsevier B.V. All rights reserved. |
Carrasco, Eduardo; Barba, Mariano; Reig, Bruno; Dieppedale, Christel; Encinar, Jose A Characterization of a Reflectarray Gathered Element With Electronic Control Using Ohmic RF MEMS and Patches Aperture-Coupled to a Delay Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (9), pp. 4190-4201, 2012, ISSN: 0018-926X. @article{Carrasco2012b, title = {Characterization of a Reflectarray Gathered Element With Electronic Control Using Ohmic RF MEMS and Patches Aperture-Coupled to a Delay}, author = {Eduardo Carrasco and Mariano Barba and Bruno Reig and Christel Dieppedale and Jose A Encinar}, doi = {10.1109/TAP.2012.2207046}, issn = {0018-926X}, year = {2012}, date = {2012-09-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {60}, number = {9}, pages = {4190-4201}, abstract = {A reflectarray element with electronic phase control implemented by ohmic MEMS switches is characterized and validated in the X-band. The proposed element is based on two patches aperture-coupled to a microstrip network with a common delay line, forming a sub-array, in order to reduce both cost and manufacturing complexity in large reflectarrays. The electrical length of the line can bemodified through the inclusion of a series switch between different segments of the microstrip line. The ohmic electrostatic switch has been designed for RF applications and manufactured on a coplanar line. The transition between the coplanar line of the MEMS and the microstrip delay line has been implemented using gold wires which have been bonded to the printed pads. This connection leads to a high impedance line. The MEMS switches have been characterized using reflection and transmission measurements on microstrip lines for deducing an equivalent circuit, which has been used in the validation of the gathered element with electronic phase control measured using waveguide simulator. The same approach has been applied to evaluate a 2-bit reflectarray element.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A reflectarray element with electronic phase control implemented by ohmic MEMS switches is characterized and validated in the X-band. The proposed element is based on two patches aperture-coupled to a microstrip network with a common delay line, forming a sub-array, in order to reduce both cost and manufacturing complexity in large reflectarrays. The electrical length of the line can bemodified through the inclusion of a series switch between different segments of the microstrip line. The ohmic electrostatic switch has been designed for RF applications and manufactured on a coplanar line. The transition between the coplanar line of the MEMS and the microstrip delay line has been implemented using gold wires which have been bonded to the printed pads. This connection leads to a high impedance line. The MEMS switches have been characterized using reflection and transmission measurements on microstrip lines for deducing an equivalent circuit, which has been used in the validation of the gathered element with electronic phase control measured using waveguide simulator. The same approach has been applied to evaluate a 2-bit reflectarray element. |
Esteban, J; Camacho-Peñalosa, C; Page, J E; Martín-Guerrero, T M Generalized Lattice Network-Based Balanced Composite Right-/Left-Handed Transmission Lines Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 60 (8), pp. 2385-2393, 2012, ISSN: 0018-9480. @article{Esteban2012, title = {Generalized Lattice Network-Based Balanced Composite Right-/Left-Handed Transmission Lines}, author = {J Esteban and C Camacho-Peñalosa and J E Page and T M Martín-Guerrero}, doi = {10.1109/TMTT.2012.2198225}, issn = {0018-9480}, year = {2012}, date = {2012-08-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {60}, number = {8}, pages = {2385-2393}, abstract = {Artificial transmission lines based on lattice network unit cells can mimic the behavior of actual metamaterial transmission lines without introducing any stopband, as opposite to their conventional counterparts based on T- or Pi-network unit cells, which can be balanced to suppress the stopbands in the transitions from left- to right-handed bands, but will always present stopbands in the right-handed- to left-handed-band transitions. The aim of this paper is twofold. First, the general properties of lattice network unit cells are discussed using simple circuit theory concepts. As a result, a systematic classification of all possible balanced lattice network-based artificial transmission line unit cells is described. Second, a novel multiband lattice network-based unit cell is presented. The proposed unit cell is made up of a coupled-microstrip section in a host microstrip and requires neither air bridges nor via-holes. Coupled lines have already been used to obtain composite right-/left-handed transmission lines, but a solution, based on wiggly lines, is given in this paper to the problem caused by the different even- and odd-mode phase velocities. As a result, the wideband capabilities of the artificial transmission line are fully exploited, as the theoretical and experimental results corroborate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Artificial transmission lines based on lattice network unit cells can mimic the behavior of actual metamaterial transmission lines without introducing any stopband, as opposite to their conventional counterparts based on T- or Pi-network unit cells, which can be balanced to suppress the stopbands in the transitions from left- to right-handed bands, but will always present stopbands in the right-handed- to left-handed-band transitions. The aim of this paper is twofold. First, the general properties of lattice network unit cells are discussed using simple circuit theory concepts. As a result, a systematic classification of all possible balanced lattice network-based artificial transmission line unit cells is described. Second, a novel multiband lattice network-based unit cell is presented. The proposed unit cell is made up of a coupled-microstrip section in a host microstrip and requires neither air bridges nor via-holes. Coupled lines have already been used to obtain composite right-/left-handed transmission lines, but a solution, based on wiggly lines, is given in this paper to the problem caused by the different even- and odd-mode phase velocities. As a result, the wideband capabilities of the artificial transmission line are fully exploited, as the theoretical and experimental results corroborate. |
Gil, Jose M An Efficient Framework for Using Higher-Order Curved Div-Conforming Elements With Cancellation of Weak Singularities in Local Space for Surface Integral Equation Artículo de revista 60 , pp. 3736–3743, 2012, ISSN: 1558-2221. @article{Gil2012, title = {An Efficient Framework for Using Higher-Order Curved Div-Conforming Elements With Cancellation of Weak Singularities in Local Space for Surface Integral Equation}, author = {Jose M Gil}, doi = {10.1109/TAP.2012.2201084}, issn = {1558-2221}, year = {2012}, date = {2012-08-00}, volume = {60}, pages = {3736--3743}, publisher = {IEEE}, abstract = {A reliable scheme for using higher-order curved div-conforming elements is presented. This procedure takes advantage of tangential basis functions developed for finite-element applications. Throughout the theorem of trace, the Helmholtz decomposition into solenoidal and nonsolenoidal subspaces is converted into a Hodge decomposition for the surface currents. Furthermore, a cancellation of the singular term appearing within the integrals is carried out acting in the local space, avoiding the difficulties associated to the curved domains, when coordinate transformations are used with this propose.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A reliable scheme for using higher-order curved div-conforming elements is presented. This procedure takes advantage of tangential basis functions developed for finite-element applications. Throughout the theorem of trace, the Helmholtz decomposition into solenoidal and nonsolenoidal subspaces is converted into a Hodge decomposition for the surface currents. Furthermore, a cancellation of the singular term appearing within the integrals is carried out acting in the local space, avoiding the difficulties associated to the curved domains, when coordinate transformations are used with this propose. |
2014 |
AEP and Mutual Coupling Formulation for Antenna Array Synthesis via Convex Optimization Artículo en actas 2014 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 1732-1733, Inst Elect Elect Engineers; Inst Elect Elect Engineers Antennas & Propagat Soc 2014, ISSN: 1522-3965, (IEEE Antennas-and-Propagation-Society International Symposium (APSURSI), Memphis, TN, JUL 06-11, 2014). |
Full-wave analysis of finite periodic cylindrical conformal arrays with Floquet spherical modes and a hybrid finite element - generalized scattering matrix method Artículo de revista JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, 28 (1), pp. 102-111, 2014, ISSN: 0920-5071. |
Broadband reflectarrays made of cells with three coplanar parallel dipoles Artículo de revista 2014. |
Broadband Reflectarray Element for Dual Polarization Made of Orthogonal Sets of Parallel Dipoles Artículo en actas 8th European Conference on Antennas and Propagation, EUCAP 2014, (The Hague, The Netherlands), 2014. |
On the Feasibility of the Complementary Strip-Slot Element to Build Planar Series-fed Arrays Artículo de revista IJMOT, International Journal of Microwave and Optical Technology, 9 (1), pp. 24-28, 2014. |
A Novel Planar Log-Periodic Array Based on the Wideband Complementary Strip-Slot Element Artículo de revista IEEE Transactions on Antennas and Propagation, 62 (11), pp. 5572-5580, 2014, ISSN: 0018-926X. |
Accurate Characterization of Multi-Resonant Reflectarray Cells by Artificial Neural Networks. Artículo en actas 2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1935-1937, 2014, ISSN: 2164-3342, (8th European Conference on Antennas and Propagation (EuCAP), Hague, NETHERLANDS, APR 06-11, 2014). |
Dynamic light bending with graphene plasmonic structures Artículo en actas International Conference on Metamaterials, Photonic Crystals and Plasmonics, 2014. |
2013 |
Experimental comparison of waveguide filters at W-band implemented by different machining processes and split-block Artículo de revista JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, 27 (18), pp. 2390-2394, 2013, ISSN: 0920-5071. |
Development of low loss waveguide filters for radio-astronomy applications Artículo de revista INFRARED PHYSICS & TECHNOLOGY, 61 , pp. 224-229, 2013, ISSN: 1350-4495. |
Multiband Circularly-Polarized Planar Array Based on the Complementary Strip-Slot Element Artículo en actas 43rd European Microwave Conference (EuMC), pp. 652-655, Nuremberg (Germany), 2013, (ISBN: 978-2-87487-031-6). |
Enhanced MoM Analysis of the Scattering by Periodic Strip Gratings in Multilayered Substrates Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (10), pp. 5088-5099, 2013, ISSN: 0018-926X. |
A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer Artículo de revista IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY, 3 (5), pp. 574-583, 2013, ISSN: 2156-342X. |
Silicon Micromachined Canonical E-Plane and H-Plane Bandpass Filters at the Terahertz Band Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 23 (6), pp. 288-290, 2013, ISSN: 1531-1309. |
Efficient numerical tool for the analysis and design of reflectarrays based on cells with three parallel dipoles Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 55 (6), pp. 1212-1216, 2013, ISSN: 0895-2477. |
Design, Manufacture and Test of a Low-Cost Shaped-Beam Reflectarray Using a Single Layer of Varying-Sized Printed Dipoles Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (6), pp. 3077-3085, 2013, ISSN: 0018-926X. |
Modelling of dual-polarisation diplexers based on enhanced multiport turnstile junctions Artículo de revista IET MICROWAVES ANTENNAS & PROPAGATION, 7 (7), pp. 485-492, 2013, ISSN: 1751-8725. |
The Complementary Strip-Slot as a Broadband Planar Array Element Artículo en actas Proceedings of the IX Iberian Meeting on Computational Electromagnetics (EIEC), Denia, Alicante (Spain), 2013. |
Microstrip series-fed array based on the strip-slot element Artículo en actas Proceedings of the 7th European Conference on Antennas and Propagation (EuCAP), pp. 1447-1450, Gothenburg (Sweden), 2013, (ISBN: 978-1-4673-2187-7). |
Design and Experimental Validation of Liquid Crystal-Based Reconfigurable Reflectarray Elements With Improved Bandwidth in F-Band Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (4, 1, SI), pp. 1704-1713, 2013, ISSN: 0018-926X. |
Design, Manufacturing and Test of a Dual-Reflectarray Antenna With Improved Bandwidth and Reduced Cross-Polarization Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 61 (3), pp. 1180-1190, 2013, ISSN: 0018-926X. |
Tunable graphene reflective cells for THz reflectarrays and generalized law of reflection Artículo de revista APPLIED PHYSICS LETTERS, 102 (10), 2013, ISSN: 0003-6951. |
Dual-Band Matching Properties of the C-Section All-Pass Network Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 61 (2), pp. 827 -832, 2013, ISSN: 0018-9480. |
Equivalent circuit of multi-aperture waveguide irises and its application in the design of compact filters Artículo en actas 2013 USNC-URSI RADIO SCIENCE MEETING (JOINT WITH AP-S SYMPOSIUM), pp. 166, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; URSI; USNC 2013, ISSN: 2572-3804, (IEEE AP-S/URSI-USNC Symposium, Lake Buena Vista, FL, JUL 07-13, 2013). |
Dual-Band Bi-Phase Waveguide Polarizer for a Novel Feeder Network without Orthomode Transducer Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 593-596, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). |
Compact Broadband Couplers Based on the Waveguide Magic-T Junction Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 151-154, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). |
Spherical Modes in Computational Electromagnetics applied to Antenna Problems Artículo en actas Dénia, Spain, 2013. |
Fast and accurate design tools for microwave filters via domain decomposition in FEM and reduced-order models Artículo en actas Dénia, Spain, 2013. |
Fast and Reliable Monostatic RCS Computation as a Function of Frequency and Angle of Observation via the Reduced-Basis Method Artículo en actas Orlando, Florida, USA, 2013. |
Broadband slot array antenna with full-space steerable pattern in a composite right/left-handed waveguide Artículo de revista Radio Science, 48 (4), pp. 406-415, 2013. |
The use of lattice networks for modelling symmetric transmission line components and discontinuities Artículo de revista Microwave and Optical Technology Letters, 55 (3), pp. 636-639, 2013. |
Nematic Liquid Crystals for Reconfigurable Millimeter Wavelength Antenna Technology Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1791+, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). |
Improvements in the MoM Analysis of 2-D Planar Multilayered Periodic Structures Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 612+, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). |
Analysis, Design and Prototyping of Reflectarray Antennas for Space Applications Artículo en actas {Edwards, RM} (Ed.): 2013 LOUGHBOROUGH ANTENNAS AND PROPAGATION CONFERENCE (LAPC), pp. 1-5, 2013, ISBN: 978-1-4799-0091-6, (Loughborough Antennas and Propagation Conference (LAPC), Loughborough Univ, Loughborough, ENGLAND, NOV 11-12, 2013). |
Preliminary Design of a Liquid Crystal-Based Reflectarray Antenna for Beam-Scanning in THz Artículo en actas 2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 2277+, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS 2013, ISSN: 1522-3965, (International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013). |
Design of a Reflectarray Antenna at 300 GHz Based on Cells with Three Coplanar Dipoles Artículo en actas 2013 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI), pp. 1350+, Inst Elect & Elect Engineers; IEEE Antennas & Propagat Soc; APS 2013, ISSN: 1522-3965, (International Symposium of the IEEE-Antennas-and-Propagation-Society, Orlando, FL, JUL 07-13, 2013). |
Reflect-Array Sub-Reflector in X-Ka Band Antenna Artículo en actas 2013 PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP), VOLS 1 AND 2, SE Univ; Univ Elect Sci & Technol China; CIE Antenna Soc; IEICE Commun Soc; IEEE Antennas & Propagat Soc; European Assoc Antennas & Propagat; Sci & Technol Antenna & Microwave Lab; Jiangsu Inst Elect; IEEE AP MTT EMC Nanjing Joint Chapter; Agilent Technologies; FEKO; Mitsubishi Elect; Bluetest se; Journal Microwaves; MMW 2013, ISBN: 978-7-5641-4279-7, (International Symposium on Antennas and Propagation (ISAP), Nanjing, PEOPLES R CHINA, OCT 23-25, 2013). |
Reflectarray Antenna at Terahertz Using Graphene Artículo de revista IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, 12 , pp. 253-256, 2013, ISSN: 1536-1225. |
Periodic and Quasi-Periodic Graphene-Based Reconfigurable Surfaces Artículo en actas PROCEEDINGS OF 2013 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS), pp. 1070-1073, Int Union Radio Sci; Inst Elect, Informat & Commun Engineers, Elect Soc 2013, ISSN: 2163-405X, (URSI International Symposium on Electromagnetic Theory (EMTS), Int Union Radio Sci Japanese Comm, Commiss B, Hiroshima, JAPAN, MAY 20-24, 2013). |
Tunable Graphene-Based Reflectarray Element for Reconfigurable Beams Artículo en actas 2013 7TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), pp. 1779-1782, 2013, ISSN: 2164-3342, (7th European Conference on Antennas and Propagation (EuCAP), Gothenburg, SWEDEN, APR 08-12, 2013). |
Graphene Antennas: Can Integration and Reconfigurability Compensate for the Loss? Artículo en actas 2013 EUROPEAN MICROWAVE CONFERENCE (EUMC), pp. 369-372, APS 2013, ISSN: 2325-0305, (43rd European Microwave Conference (EuMC), Nuremberg, GERMANY, OCT 07-10, 2013). |
2012 |
Planar Broadband Slot Radiating Element Based on Microstrip-Slot Coupling for Series-fed Arrays Artículo de revista IEEE Transactions on Antennas and Propagation, 60 (12), pp. 6037-6042, 2012, ISSN: 0018-926X. |
X-Band Reflectarray Antenna With Switching-Beam Using PIN Diodes and Gathered Elements Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (12), pp. 5700-5708, 2012, ISSN: 0018-926X. |
Efficient Combined Array Thinning and Weighting for Pattern Synthesis With a Nested Optimization Scheme Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (11), pp. 5107-5117, 2012, ISSN: 0018-926X. |
Reduction of cross-polarization in offset reflectarrays using two layers of varying-sized patches Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 54 (11), pp. 2449-2454, 2012, ISSN: 0895-2477. |
Low-Loss Elliptical Response Filter at 100 GHz Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 22 (9), pp. 459-461, 2012, ISSN: 1531-1309. |
Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis Artículo de revista FUSION ENGINEERING AND DESIGN, 87 (9), pp. 1662-1666, 2012, ISSN: 0920-3796. |
Characterization of a Reflectarray Gathered Element With Electronic Control Using Ohmic RF MEMS and Patches Aperture-Coupled to a Delay Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 60 (9), pp. 4190-4201, 2012, ISSN: 0018-926X. |
Generalized Lattice Network-Based Balanced Composite Right-/Left-Handed Transmission Lines Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 60 (8), pp. 2385-2393, 2012, ISSN: 0018-9480. |
An Efficient Framework for Using Higher-Order Curved Div-Conforming Elements With Cancellation of Weak Singularities in Local Space for Surface Integral Equation Artículo de revista 60 , pp. 3736–3743, 2012, ISSN: 1558-2221. |
