2021 |
Vaquero, Álvaro F; Arrebola, Manuel; Pino, Marcos Rodriguez; Florencio, Rafael; Encinar, José A Demonstration of a Reflectarray With Near-Field Amplitude and Phase Constraints as Compact Antenna Test Range Probe for 5G New Radio Devices Artículo de revista IEEE Transactions on Antennas and Propagation, 69 (5), pp. 2715-2726, 2021, ISSN: 1558-2221. @article{9234694, title = {Demonstration of a Reflectarray With Near-Field Amplitude and Phase Constraints as Compact Antenna Test Range Probe for 5G New Radio Devices}, author = {Álvaro F Vaquero and Manuel Arrebola and Marcos Rodriguez Pino and Rafael Florencio and José A Encinar}, doi = {10.1109/TAP.2020.3030969}, issn = {1558-2221}, year = {2021}, date = {2021-05-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {69}, number = {5}, pages = {2715-2726}, abstract = {In this work, a reflectarray is proposed to be used as a probe of reduced and portable compact-antenna-test range for 5G new radio devices. The reflectarray works at 28 GHz and produces a quiet zone in the near-field region of the antenna. Considering that the quiet zone specifications are established in terms of the amplitude and phase ripple, a synthesis technique is presented to optimize the near field in the Fresnel region of a reflectarray with amplitude and phase constraints. The proposed technique is based on the generalized intersection approach using the Levenberg–Marquardt algorithm as its backward projector obtaining a novel technique in near-field synthesis. This technique is applied to improve the quiet zone radiated by the proposed reflectarray, overcoming the amplitude and phase limitations of the initial configuration. The solution provided by this process is used to design and manufacture a reflectarray based on a three-parallel-dipole cell. Finally, the prototype is measured in a near-field planar range facility in order to evaluate the radiated quiet zone and demonstrate the methodology. The prototype satisfies the tight requirements in amplitude and phase, obtaining promising results.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, a reflectarray is proposed to be used as a probe of reduced and portable compact-antenna-test range for 5G new radio devices. The reflectarray works at 28 GHz and produces a quiet zone in the near-field region of the antenna. Considering that the quiet zone specifications are established in terms of the amplitude and phase ripple, a synthesis technique is presented to optimize the near field in the Fresnel region of a reflectarray with amplitude and phase constraints. The proposed technique is based on the generalized intersection approach using the Levenberg–Marquardt algorithm as its backward projector obtaining a novel technique in near-field synthesis. This technique is applied to improve the quiet zone radiated by the proposed reflectarray, overcoming the amplitude and phase limitations of the initial configuration. The solution provided by this process is used to design and manufacture a reflectarray based on a three-parallel-dipole cell. Finally, the prototype is measured in a near-field planar range facility in order to evaluate the radiated quiet zone and demonstrate the methodology. The prototype satisfies the tight requirements in amplitude and phase, obtaining promising results. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Rodriguez-Vaqueiro, Yolanda; Encinar, Jose A; Pino, Antonio; Arias, Marcos; Toso, Giovanni Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band Artículo de revista IEEE Transactions on Antennas and Propagation, 69 (5), pp. 2673-2685, 2021, ISSN: 1558-2221. @article{9234051, title = {Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Yolanda Rodriguez-Vaqueiro and Jose A Encinar and Antonio Pino and Marcos Arias and Giovanni Toso}, doi = {10.1109/TAP.2020.3030942}, issn = {1558-2221}, year = {2021}, date = {2021-05-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {69}, number = {5}, pages = {2673-2685}, abstract = {This contribution describes the design of a multibeam parabolic reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at the transmission (Tx) and reception (Rx) frequencies in the Ka-band. The variable rotation technique (VRT) has been applied to the reflectarray cells based on two types of resonant elements, which makes it possible to provide orthogonal beams at Tx and Rx, as well as to implement an in-band optimization procedure to reduce the cross-polarization. A 90 cm parabolic reflectarray has been designed, manufactured, and tested to produce multiple adjacent beams in RHCP and LHCP at both 20 and 30 GHz. The results are satisfactory and validate the concept of generating two spaced beams in the orthogonal CP by a single feed, changing the polarization of the beam between Tx and Rx. This concept can be suitable for multispot satellites in the Ka-band, enabling to halve the number of onboard antennas and feeds.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This contribution describes the design of a multibeam parabolic reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at the transmission (Tx) and reception (Rx) frequencies in the Ka-band. The variable rotation technique (VRT) has been applied to the reflectarray cells based on two types of resonant elements, which makes it possible to provide orthogonal beams at Tx and Rx, as well as to implement an in-band optimization procedure to reduce the cross-polarization. A 90 cm parabolic reflectarray has been designed, manufactured, and tested to produce multiple adjacent beams in RHCP and LHCP at both 20 and 30 GHz. The results are satisfactory and validate the concept of generating two spaced beams in the orthogonal CP by a single feed, changing the polarization of the beam between Tx and Rx. This concept can be suitable for multispot satellites in the Ka-band, enabling to halve the number of onboard antennas and feeds. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Rodriguez-Vaqueiro, Yolanda; Encinar, Jose A; Pino, Antonio; Arias, Marcos; Arrebola, Manuel; Toso, Giovanni Parabolic Reflectarray Antenna to Generate Multiple Beams in Dual-Frequency and Dual-Circular Polarization Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2021. @inproceedings{9410988, title = {Parabolic Reflectarray Antenna to Generate Multiple Beams in Dual-Frequency and Dual-Circular Polarization}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Yolanda Rodriguez-Vaqueiro and Jose A Encinar and Antonio Pino and Marcos Arias and Manuel Arrebola and Giovanni Toso}, doi = {10.23919/EuCAP51087.2021.9410988}, year = {2021}, date = {2021-03-01}, booktitle = {2021 15th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-5}, abstract = {This contribution presents the design and simulations of a 1.8-m parabolic reflectarray to generate a multi-spot coverage from a geostationary satellite. The antenna has been designed to generate two spaced beams per feed in orthogonal circular polarizations (CP) simultaneously at transmission and reception frequencies in Ka-band. The parabolic reflectarray operates by the variable rotation technique independently applied at 19.7 GHz and 29.5 GHz to split the orthogonal CP beams focused by the parabolic surface. The proposed design technique and the simulated results have been experimentally validated by the manufacturing and testing of a 0.9-m parabolic reflectarray with the same operating principle. The proposed antenna technology can be used to provide multispot coverages in Kaband from geostationary satellites, with the advantage of reducing to one-half the number of antennas and feed-chains commonly required using conventional reflectors.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution presents the design and simulations of a 1.8-m parabolic reflectarray to generate a multi-spot coverage from a geostationary satellite. The antenna has been designed to generate two spaced beams per feed in orthogonal circular polarizations (CP) simultaneously at transmission and reception frequencies in Ka-band. The parabolic reflectarray operates by the variable rotation technique independently applied at 19.7 GHz and 29.5 GHz to split the orthogonal CP beams focused by the parabolic surface. The proposed design technique and the simulated results have been experimentally validated by the manufacturing and testing of a 0.9-m parabolic reflectarray with the same operating principle. The proposed antenna technology can be used to provide multispot coverages in Kaband from geostationary satellites, with the advantage of reducing to one-half the number of antennas and feed-chains commonly required using conventional reflectors. |
Abdollahvand, Mousa; Forooraghi, Keyvan; Atlasbaf, Zahra; Martinez-de-Rioja, Eduardo; Encinar, Jose A; Ebrahimi, Amir; Ghosh, Saptarshi Reconfigurable FSS Based on PIN Diodes for Shared-Aperture X/Ka-Band Antennas Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2021. @inproceedings{9411211, title = {Reconfigurable FSS Based on PIN Diodes for Shared-Aperture X/Ka-Band Antennas}, author = {Mousa Abdollahvand and Keyvan Forooraghi and Zahra Atlasbaf and Eduardo Martinez-de-Rioja and Jose A Encinar and Amir Ebrahimi and Saptarshi Ghosh}, doi = {10.23919/EuCAP51087.2021.9411211}, year = {2021}, date = {2021-03-01}, booktitle = {2021 15th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-4}, abstract = {This contribution presents a reconfigurable frequency selective surface (FSS) for shared-aperture satellite antennas in X and Ka bands. The FSS has been designed to be reflective at 20 and 30 GHz (transmit and receive frequencies in Ka-band) and to allow switching of transmission and reflection responses in X-band (between 9 and 12 GHz). The FSS unit cell comprises a multi-layer structure, and reconfigurability is achieved using four PIN diodes. An equivalent circuit model has been developed explaining the operating principle of the proposed FSS. The active FSS provides a stable performance for different polarizations under oblique incidence angles.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution presents a reconfigurable frequency selective surface (FSS) for shared-aperture satellite antennas in X and Ka bands. The FSS has been designed to be reflective at 20 and 30 GHz (transmit and receive frequencies in Ka-band) and to allow switching of transmission and reflection responses in X-band (between 9 and 12 GHz). The FSS unit cell comprises a multi-layer structure, and reconfigurability is achieved using four PIN diodes. An equivalent circuit model has been developed explaining the operating principle of the proposed FSS. The active FSS provides a stable performance for different polarizations under oblique incidence angles. |
Martinez-de-Rioja, Eduardo; Vaquero, Álvaro F; Arrebola, Manuel; Carrasco, Eduardo; Encinar, Jose A; Achour, Maha Passive Dual-Polarized Shaped-Beam Reflectarrays to Improve Coverage in Millimeter-Wave 5G Networks Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2021. @inproceedings{9411196, title = {Passive Dual-Polarized Shaped-Beam Reflectarrays to Improve Coverage in Millimeter-Wave 5G Networks}, author = {Eduardo Martinez-de-Rioja and Álvaro F Vaquero and Manuel Arrebola and Eduardo Carrasco and Jose A Encinar and Maha Achour}, doi = {10.23919/EuCAP51087.2021.9411196}, year = {2021}, date = {2021-03-01}, booktitle = {2021 15th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-5}, abstract = {This contribution presents the design of a passive shaped-beam reflectarray to improve coverage in 5G cellular networks. The reflectarray has been designed to produce a broadened and deflected beam in dual-linear polarization at 27.7 GHz. The unit cell provides more than 360^o range of phase variation and a robust performance under large angles of incidence (around 50^o ). Phase-only synthesis has been applied to obtain the required phase distribution on the reflectarray to fulfill the scenario requirements in terms of beam pointing and HPBW. The designed reflectarray exhibits a stable behavior within the 27.2-28.2 GHz band, showing the potential of this technology for millimeter-wave 5G communications.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution presents the design of a passive shaped-beam reflectarray to improve coverage in 5G cellular networks. The reflectarray has been designed to produce a broadened and deflected beam in dual-linear polarization at 27.7 GHz. The unit cell provides more than 360^o range of phase variation and a robust performance under large angles of incidence (around 50^o ). Phase-only synthesis has been applied to obtain the required phase distribution on the reflectarray to fulfill the scenario requirements in terms of beam pointing and HPBW. The designed reflectarray exhibits a stable behavior within the 27.2-28.2 GHz band, showing the potential of this technology for millimeter-wave 5G communications. |
2020 |
Florencio, Rafael; Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Encinar, Jose A; Boix, Rafael R; Losada, Vicente Design of Ku- and Ka-Band Flat Dual Circular Polarized Reflectarrays by Combining Variable Rotation Technique and Element Size Variation Artículo de revista Electronics, 9 (6), pp. 985, 2020. @article{Florencio_2020, title = {Design of Ku- and Ka-Band Flat Dual Circular Polarized Reflectarrays by Combining Variable Rotation Technique and Element Size Variation}, author = {Rafael Florencio and Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Jose A. Encinar and Rafael R. Boix and Vicente Losada}, url = {https://doi.org/10.3390%2Felectronics9060985}, doi = {10.3390/electronics9060985}, year = {2020}, date = {2020-06-01}, journal = {Electronics}, volume = {9}, number = {6}, pages = {985}, publisher = {{MDPI} {AG}}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Martinez-de-Rioja, Eduardo; Encinar, Jose A; Toso, Giovanni Bifocal Dual-Reflectarray Antenna to Generate a Complete Multiple Spot Beam Coverage for Satellite Communications in Ka-Band Artículo de revista Electronics, 9 (6), pp. 961, 2020. @article{Martinez_de_Rioja_2020, title = {Bifocal Dual-Reflectarray Antenna to Generate a Complete Multiple Spot Beam Coverage for Satellite Communications in Ka-Band}, author = {Eduardo Martinez-de-Rioja and Jose A. Encinar and Giovanni Toso}, url = {https://doi.org/10.3390%2Felectronics9060961}, doi = {10.3390/electronics9060961}, year = {2020}, date = {2020-06-01}, journal = {Electronics}, volume = {9}, number = {6}, pages = {961}, publisher = {{MDPI} {AG}}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Gil, Jose M; Conde-Pumpido, Fernando Efficient higher-order discretization of the magnetic field integral equation by means of vector spaces with a solenoidal-no solenoidal decomposition Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 62 (6), pp. 2168-2173, 2020, ISSN: 0895-2477. @article{Gil2020, title = {Efficient higher-order discretization of the magnetic field integral equation by means of vector spaces with a solenoidal-no solenoidal decomposition}, author = {Jose M Gil and Fernando Conde-Pumpido}, doi = {10.1002/mop.32299}, issn = {0895-2477}, year = {2020}, date = {2020-06-01}, journal = {MICROWAVE AND OPTICAL TECHNOLOGY LETTERS}, volume = {62}, number = {6}, pages = {2168-2173}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Abdollahvand, M; Forooraghi, K; Encinar, Jose A; Atlasbaf, Z; Martinez-de-Rioja, Eduardo A 20/30 GHz Reflectarray Backed by FSS for Shared Aperture Ku/Ka-Band Satellite Communication Antennas Artículo de revista IEEE Antennas and Wireless Propagation Letters, 19 (4), pp. 566-570, 2020, ISSN: 1548-5757. @article{Abdollahvand2020, title = {A 20/30 GHz Reflectarray Backed by FSS for Shared Aperture Ku/Ka-Band Satellite Communication Antennas}, author = {M Abdollahvand and K Forooraghi and Jose A Encinar and Z Atlasbaf and Eduardo Martinez-de-Rioja}, doi = {10.1109/LAWP.2020.2972024}, issn = {1548-5757}, year = {2020}, date = {2020-04-01}, journal = {IEEE Antennas and Wireless Propagation Letters}, volume = {19}, number = {4}, pages = {566-570}, abstract = {This letter presents a dual-polarized and dual-frequency reflectarray backed by a frequency selective surface (FSS) with application to shared aperture Ku/Ka-band satellite communication antennas. The reflectarray has been designed to operate simultaneously at 20 and 30 GHz (downlink and uplink frequencies in Ka-band) using a single-layer configuration, where the printed elements are etched on the upper substrate of a two-layer triband FSS. The FSS has been designed to be transmissive at 12 GHz (downlink frequency in Ku-band) and reflective at 20 and 30 GHz. An 18 × 18-cm2 prototype has been fabricated and tested, showing a good matching with the simulations. The measured gains are 28.5 dBi at 20 GHz and 32.25 dBi at 30 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This letter presents a dual-polarized and dual-frequency reflectarray backed by a frequency selective surface (FSS) with application to shared aperture Ku/Ka-band satellite communication antennas. The reflectarray has been designed to operate simultaneously at 20 and 30 GHz (downlink and uplink frequencies in Ka-band) using a single-layer configuration, where the printed elements are etched on the upper substrate of a two-layer triband FSS. The FSS has been designed to be transmissive at 12 GHz (downlink frequency in Ku-band) and reflective at 20 and 30 GHz. An 18 × 18-cm2 prototype has been fabricated and tested, showing a good matching with the simulations. The measured gains are 28.5 dBi at 20 GHz and 32.25 dBi at 30 GHz. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Encinar, Jose A; Florencio, Rafael; Boix, Rafael R Bandwidth Improvement of Reflectarray Cells Using Variable Rotation Technique at Two Frequencies for Dual Circular Polarization Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2020. @inproceedings{9135394, title = {Bandwidth Improvement of Reflectarray Cells Using Variable Rotation Technique at Two Frequencies for Dual Circular Polarization}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Jose A Encinar and Rafael Florencio and Rafael R Boix}, doi = {10.23919/EuCAP48036.2020.9135394}, year = {2020}, date = {2020-03-01}, booktitle = {2020 14th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-4}, abstract = {The bandwidth behavior has been studied and improved for a reflectarray cell formed by two symmetric arcs and dipoles printed on two layers, which uses Variable Rotation Technique at two frequencies for dual circular polarization. First, the appropriate thickness of the dielectric layers have been selected to improve the bandwidth. Then, an optimization routine has been applied to minimize the phase errors in a frequency band from 29.25-29.75 GHz. As a result of this optimization, the phase errors have been drastically reduced from ± 40 to ± 3 degree.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The bandwidth behavior has been studied and improved for a reflectarray cell formed by two symmetric arcs and dipoles printed on two layers, which uses Variable Rotation Technique at two frequencies for dual circular polarization. First, the appropriate thickness of the dielectric layers have been selected to improve the bandwidth. Then, an optimization routine has been applied to minimize the phase errors in a frequency band from 29.25-29.75 GHz. As a result of this optimization, the phase errors have been drastically reduced from ± 40 to ± 3 degree. |
Martinez-de-Rioja, Eduardo; Encinar, Jose A Design of a Wideband Linear-to-Circular Polarizing Reflector for Ka-band Satellite Applications Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2020. @inproceedings{9135706, title = {Design of a Wideband Linear-to-Circular Polarizing Reflector for Ka-band Satellite Applications}, author = {Eduardo Martinez-de-Rioja and Jose A Encinar}, doi = {10.23919/EuCAP48036.2020.9135706}, year = {2020}, date = {2020-03-01}, booktitle = {2020 14th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-4}, abstract = {This contribution presents a low-profile linear-to-circular polarizing reflector with wideband operation in Kaband. The polarizing cell consists of three parallel dipoles placed with 45° slant with respect to the direction of the incident linearly polarized field. The lengths of the dipoles are adjusted cell by cell through a dual-frequency optimization process, which accounts for the real incidence angles on each cell. A 25x25 cm flat polarizing reflector prototype has been fabricated and tested to validate the concept. The measured axial ratio is lower than 1.8 dB within the 19-30 GHz band (a relative bandwidth of 45%), and good matching with the simulations is obtained. The proposed polarizing reflector has applications in novel multibeam antenna configurations for Ka-band satellites.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution presents a low-profile linear-to-circular polarizing reflector with wideband operation in Kaband. The polarizing cell consists of three parallel dipoles placed with 45° slant with respect to the direction of the incident linearly polarized field. The lengths of the dipoles are adjusted cell by cell through a dual-frequency optimization process, which accounts for the real incidence angles on each cell. A 25x25 cm flat polarizing reflector prototype has been fabricated and tested to validate the concept. The measured axial ratio is lower than 1.8 dB within the 19-30 GHz band (a relative bandwidth of 45%), and good matching with the simulations is obtained. The proposed polarizing reflector has applications in novel multibeam antenna configurations for Ka-band satellites. |
Martinez-de-Rioja, Daniel; Encinar, Jose A; Rodriguez-Vaqueiro, Yolanda; Pino, Antonio Preliminary Simulations of a 1.8-m Parabolic Reflectarray in a Geostationary Satellite to Generate a Complete Multi-Spot Coverage for Tx Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2020. @inproceedings{9135807, title = {Preliminary Simulations of a 1.8-m Parabolic Reflectarray in a Geostationary Satellite to Generate a Complete Multi-Spot Coverage for Tx}, author = {Daniel Martinez-de-Rioja and Jose A Encinar and Yolanda Rodriguez-Vaqueiro and Antonio Pino}, doi = {10.23919/EuCAP48036.2020.9135807}, year = {2020}, date = {2020-03-01}, booktitle = {2020 14th European Conference on Antennas and Propagation (EuCAP)}, pages = {1-5}, abstract = {A parabolic reflectarray antenna has been proposed to generate a complete cellular coverage in transmission to provide broadband services from a communication satellite in Ka-band. Two different approaches have been evaluated to design a parabolic reflectarray able to generate four spaced beams per feed in four different combinations of frequency and polarization. A 1.8 m parabolic reflectarray has been simulated when it is illuminated by a feed block of 27 horns. The results show the capacity to generate 108 spot beams in good agreement with the requirements imposed in satellite communications. The proposed concept could be used to reduce the number of on-board antennas and feed chains required to generate a multispot coverage in Ka-band.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A parabolic reflectarray antenna has been proposed to generate a complete cellular coverage in transmission to provide broadband services from a communication satellite in Ka-band. Two different approaches have been evaluated to design a parabolic reflectarray able to generate four spaced beams per feed in four different combinations of frequency and polarization. A 1.8 m parabolic reflectarray has been simulated when it is illuminated by a feed block of 27 horns. The results show the capacity to generate 108 spot beams in good agreement with the requirements imposed in satellite communications. The proposed concept could be used to reduce the number of on-board antennas and feed chains required to generate a multispot coverage in Ka-band. |
Martinez-de-Rioja, Daniel; Encinar, Jose A; Martinez-de-Rioja, Eduardo; Rodriguez-Vaqueiro, Yolanda; Pino, Antonio Advanced Reflectarray Antennas for Multispot Coverages in Ka Band Artículo en actas 2020 International Workshop on Antenna Technology (iWAT), pp. 1-4, 2020. @inproceedings{MartinezdeRioja2020, title = {Advanced Reflectarray Antennas for Multispot Coverages in Ka Band}, author = {Daniel Martinez-de-Rioja and Jose A Encinar and Eduardo Martinez-de-Rioja and Yolanda Rodriguez-Vaqueiro and Antonio Pino}, doi = {10.1109/iWAT48004.2020.1570608647}, year = {2020}, date = {2020-02-01}, booktitle = {2020 International Workshop on Antenna Technology (iWAT)}, pages = {1-4}, abstract = {This contribution proposes three different multibeam antenna farms based on reflectarrays to be used on board broadband communication satellites in Ka-band. The proposed antenna configurations make it possible to generate multispot coverages in a more efficient way than the antenna systems currently used, since they require a smaller number of antennas on board the satellite. Simulated results are presented for the three antenna configurations to evaluate their compliance with the system requirements.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution proposes three different multibeam antenna farms based on reflectarrays to be used on board broadband communication satellites in Ka-band. The proposed antenna configurations make it possible to generate multispot coverages in a more efficient way than the antenna systems currently used, since they require a smaller number of antennas on board the satellite. Simulated results are presented for the three antenna configurations to evaluate their compliance with the system requirements. |
Buesa-Zubiria, Ana María; Esteban, J Design of Broadband Doubly Asymmetrical Branch-Line Directional Couplers Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 68 (4), pp. 1439-1451, 2020, ISSN: 1557-9670. @article{BuesaZubiria2020, title = {Design of Broadband Doubly Asymmetrical Branch-Line Directional Couplers}, author = {Ana María Buesa-Zubiria and J Esteban}, doi = {10.1109/TMTT.2019.2953904}, issn = {1557-9670}, year = {2020}, date = {2020-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {68}, number = {4}, pages = {1439-1451}, abstract = {An analytic broadband design method for four-port N-branch branch-line couplers with outputs terminated by arbitrary impedances is given. An alternative, more practical design method has also been included, which avoids impedance discontinuities in the branches and retrieves the outputs-in-quadrature property lost in the asymmetrization. The doubly asymmetrical couplers so obtained are then used in a proposed design methodology for three-way power dividers that can include, if desired, an impedance level transformation. This article relies on the analysis of a class of asymmetrical structures by means of the odd and even excitations. Therefore, the formalization of this analysis is also detailed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An analytic broadband design method for four-port N-branch branch-line couplers with outputs terminated by arbitrary impedances is given. An alternative, more practical design method has also been included, which avoids impedance discontinuities in the branches and retrieves the outputs-in-quadrature property lost in the asymmetrization. The doubly asymmetrical couplers so obtained are then used in a proposed design methodology for three-way power dividers that can include, if desired, an impedance level transformation. This article relies on the analysis of a class of asymmetrical structures by means of the odd and even excitations. Therefore, the formalization of this analysis is also detailed. |
Hernández-Escobar, Alberto; Abdo-Sánchez, E; Esteban, J; Martín-Guerrero, T M; Camacho-Peñalosa, C Broadband Determination of the Even- and Odd-Mode Propagation Constants of Coupled Lines Based on Two-Port Measurements Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 68 (2), pp. 648-654, 2020, ISSN: 0018-9480. @article{HernandezEscobar2020, title = {Broadband Determination of the Even- and Odd-Mode Propagation Constants of Coupled Lines Based on Two-Port Measurements}, author = {Alberto Hernández-Escobar and E Abdo-Sánchez and J Esteban and T M Martín-Guerrero and C Camacho-Peñalosa}, doi = {10.1109/TMTT.2019.2952115}, issn = {0018-9480}, year = {2020}, date = {2020-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {68}, number = {2}, pages = {648-654}, abstract = {We describe a method for the broadband measurement of the even- and odd-mode propagation constants of symmetrical coupled transmission lines. The main advantage of the method, its simplicity, lies in the lack of need for four-port measurements. Only two-port measurements are required, and thus just a two-port vector network analyzer (VNA). The accuracy of the results can be increased at the cost of a higher number of measured coupled-line lengths. The new approach has been successfully applied for the determination of coupled microstrip lines in the 2- to 20-GHz frequency band in both simulated and experimental cases. A brief discussion about the repeatability of the microstrip launcher and the adverse effects of radiation is included.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We describe a method for the broadband measurement of the even- and odd-mode propagation constants of symmetrical coupled transmission lines. The main advantage of the method, its simplicity, lies in the lack of need for four-port measurements. Only two-port measurements are required, and thus just a two-port vector network analyzer (VNA). The accuracy of the results can be increased at the cost of a higher number of measured coupled-line lengths. The new approach has been successfully applied for the determination of coupled microstrip lines in the 2- to 20-GHz frequency band in both simulated and experimental cases. A brief discussion about the repeatability of the microstrip launcher and the adverse effects of radiation is included. |
Martinez-de-Rioja, Daniel; Florencio, Rafael; Martinez-de-Rioja, Eduardo; Arrebola, Manuel; Encinar, Jose A; Boix, Rafael R Dual-Band Reflectarray to Generate Two Spaced Beams in Orthogonal Circular Polarization by Variable Rotation Technique Artículo de revista IEEE Transactions on Antennas and Propagation, pp. 1-1, 2020, ISSN: 1558-2221. @article{MartinezdeRioja2020b, title = {Dual-Band Reflectarray to Generate Two Spaced Beams in Orthogonal Circular Polarization by Variable Rotation Technique}, author = {Daniel Martinez-de-Rioja and Rafael Florencio and Eduardo Martinez-de-Rioja and Manuel Arrebola and Jose A Encinar and Rafael R Boix}, doi = {10.1109/TAP.2020.2975294}, issn = {1558-2221}, year = {2020}, date = {2020-01-01}, journal = {IEEE Transactions on Antennas and Propagation}, pages = {1-1}, abstract = {This contribution describes the design of a reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies in Ka-band. The discrimination in CP is achieved by the variable rotation technique (VRT) and its dual band operation is validated for the lme by the manufacture and measurement of a 25 cm x 25 cm reflectarray demonstrator. Moreover, an optimization procedure has been implemented to improve the narrowband performance of the VRT (which leads to high cross-polar levels when VRT is applied). The reflectarray prototype has been designed to deviate ±5° the beams radiated by a dual-CP feed-horn at Tx and Rx frequencies in the Ka-band (20/30 GHz). The results are satisfactory and validate the concept of generating two spaced beams in orthogonal CP and dual band by VRT with a single feed. This concept can be suitable for multiple spot satellites in Ka-band, enabling a reduction in the number of antennas and feeds needed to provide the multi-spot coverage.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This contribution describes the design of a reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies in Ka-band. The discrimination in CP is achieved by the variable rotation technique (VRT) and its dual band operation is validated for the lme by the manufacture and measurement of a 25 cm x 25 cm reflectarray demonstrator. Moreover, an optimization procedure has been implemented to improve the narrowband performance of the VRT (which leads to high cross-polar levels when VRT is applied). The reflectarray prototype has been designed to deviate ±5° the beams radiated by a dual-CP feed-horn at Tx and Rx frequencies in the Ka-band (20/30 GHz). The results are satisfactory and validate the concept of generating two spaced beams in orthogonal CP and dual band by VRT with a single feed. This concept can be suitable for multiple spot satellites in Ka-band, enabling a reduction in the number of antennas and feeds needed to provide the multi-spot coverage. |
Martinez-de-Rioja, Eduardo; Encinar, Jose A; Pino, Antonio; Rodriguez-Vaqueiro, Yolanda Broadband Linear-to-Circular Polarizing Reflector for Space Applications in Ka-Band Artículo de revista IEEE Transactions on Antennas and Propagation, pp. 1-1, 2020, ISSN: 1558-2221. @article{MartinezdeRioja2020a, title = {Broadband Linear-to-Circular Polarizing Reflector for Space Applications in Ka-Band}, author = {Eduardo Martinez-de-Rioja and Jose A Encinar and Antonio Pino and Yolanda Rodriguez-Vaqueiro}, doi = {10.1109/TAP.2020.2975617}, issn = {1558-2221}, year = {2020}, date = {2020-01-01}, journal = {IEEE Transactions on Antennas and Propagation}, pages = {1-1}, abstract = {This communication presents a novel low-profile broadband polarizing reflector to convert dual linear polarization (LP) into dual circular polarization (CP). The polarizing cell is based on printed dipole technology and presents a wideband performance in Ka-band. The dimensions of the printed dipoles are adjusted cell by cell to improve the reflection phase performance against variations in the incidence angles or in the cell dimensions. A 25-cm flat polarizing reflector demonstrator has been designed, fabricated and tested. The design has been optimized for transmit (19.2-20.2 GHz) and receive (29-30 GHz) frequencies in Ka-band, but the broadband behavior of the cell provides satisfactory results also at the intermediate frequencies. The measured patterns show a good agreement with the simulations, with an axial ratio lower than 1.8 dB within the 19.2-30 GHz band. The proposed polarizing reflector can be used for novel multibeam antenna configurations to produce multi-spot coverage in Ka-band with a smaller number of apertures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This communication presents a novel low-profile broadband polarizing reflector to convert dual linear polarization (LP) into dual circular polarization (CP). The polarizing cell is based on printed dipole technology and presents a wideband performance in Ka-band. The dimensions of the printed dipoles are adjusted cell by cell to improve the reflection phase performance against variations in the incidence angles or in the cell dimensions. A 25-cm flat polarizing reflector demonstrator has been designed, fabricated and tested. The design has been optimized for transmit (19.2-20.2 GHz) and receive (29-30 GHz) frequencies in Ka-band, but the broadband behavior of the cell provides satisfactory results also at the intermediate frequencies. The measured patterns show a good agreement with the simulations, with an axial ratio lower than 1.8 dB within the 19.2-30 GHz band. The proposed polarizing reflector can be used for novel multibeam antenna configurations to produce multi-spot coverage in Ka-band with a smaller number of apertures. |
Perez-Palomino, Gerardo; Page, J E Bi-Mode Foster’s Equivalent Circuit of Arbitrary Planar Periodic Structures and its Application to Design Polarization Controller Devices Artículo de revista 2020. @article{PerezPalomino2020, title = {Bi-Mode Foster’s Equivalent Circuit of Arbitrary Planar Periodic Structures and its Application to Design Polarization Controller Devices}, author = {Gerardo Perez-Palomino and J E Page}, doi = {10.1109/tap.2020.2976506}, year = {2020}, date = {2020-01-01}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Zang, Jiawei; Carrasco, Eduardo; Wang, Xuetian; Alvarez-Melcon, Alejandro; Gomez-Diaz, Juan Sebastian Analysis and Design of Reflectarray Antennas Based on Delay Lines: A Filter Perspective Artículo de revista IEEE ACCESS, 8 , pp. 44947-44956, 2020, ISSN: 2169-3536. @article{ISI:000524712900042, title = {Analysis and Design of Reflectarray Antennas Based on Delay Lines: A Filter Perspective}, author = {Jiawei Zang and Eduardo Carrasco and Xuetian Wang and Alejandro Alvarez-Melcon and Juan Sebastian Gomez-Diaz}, doi = {10.1109/ACCESS.2020.2976643}, issn = {2169-3536}, year = {2020}, date = {2020-00-00}, journal = {IEEE ACCESS}, volume = {8}, pages = {44947-44956}, abstract = {The analysis and design of reflectarray (RA) antennas based in delay lines is introduced for the first time from a filter perspective. To this purpose, each unit-cell of the RA is considered as a network composed of two ports, one being the delay line and the other one the free-space. This approach allows to borrow the coupling matrix formalism from filter theory and apply it to design unit-cells exhibiting broadband operation together with very sharp frequency responses. The concept is demonstrated with the aid of planar printed unit-cells coupled to substrate integrated waveguides (SIWs) through slots, a configuration that offers significant advantages to shape its frequency response while providing relatively low loss. With the aim of validation, a third order filter structure integrated in SIW-based unit-cells has been experimentally tested using the waveguide simulator technique, at a center frequency of 9 GHz. Measurements demonstrate a high-quality linear phase variation and range, and large frequency selectivity together with broadband response for the element of about 18 & x0025;. The experimental results show the feasibility of this approach for the design of broadband reflectarray antennas exhibiting sharp gain responses. To illustrate the concept, a medium size reflectarray has been theoretically designed using the proposed unit cell at 9 GHz, showing a directive beam with 35.8 dB gain, sharp gain selectivity over 18 dB, and confirms the wide band operation with 20.3 & x0025; bandwidth for a 3 dB gain variation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The analysis and design of reflectarray (RA) antennas based in delay lines is introduced for the first time from a filter perspective. To this purpose, each unit-cell of the RA is considered as a network composed of two ports, one being the delay line and the other one the free-space. This approach allows to borrow the coupling matrix formalism from filter theory and apply it to design unit-cells exhibiting broadband operation together with very sharp frequency responses. The concept is demonstrated with the aid of planar printed unit-cells coupled to substrate integrated waveguides (SIWs) through slots, a configuration that offers significant advantages to shape its frequency response while providing relatively low loss. With the aim of validation, a third order filter structure integrated in SIW-based unit-cells has been experimentally tested using the waveguide simulator technique, at a center frequency of 9 GHz. Measurements demonstrate a high-quality linear phase variation and range, and large frequency selectivity together with broadband response for the element of about 18 & x0025;. The experimental results show the feasibility of this approach for the design of broadband reflectarray antennas exhibiting sharp gain responses. To illustrate the concept, a medium size reflectarray has been theoretically designed using the proposed unit cell at 9 GHz, showing a directive beam with 35.8 dB gain, sharp gain selectivity over 18 dB, and confirms the wide band operation with 20.3 & x0025; bandwidth for a 3 dB gain variation. |
2019 |
Montejo-Garai, Jose R; Leal-Sevillano, Carlos A; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Development of a high-performance W-band duplexer for plasma diagnosis using a single band with dual circular polarization Artículo de revista NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 947 , 2019, ISSN: 0168-9002. @article{MontejoGarai2019, title = {Development of a high-performance W-band duplexer for plasma diagnosis using a single band with dual circular polarization}, author = {Jose R Montejo-Garai and Carlos A Leal-Sevillano and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1016/j.nima.2019.162712}, issn = {0168-9002}, year = {2019}, date = {2019-12-01}, journal = {NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, volume = {947}, abstract = {This work presents the design and experimental validation of a high performance, compact, waveguide duplexer operating from 91.5 to 96.5 GHz for its integration in diverse W-band microwave equipment as in plasma diagnosis applications. It uses a single frequency band, with two signals discriminated by different orthogonal circular polarization, which is generated by means of a septum orthomode transducer (OMT) polarizer. Moreover, this component is optimized loaded with the horn antenna for improving the overall system performance. It is explained how these two components are integrated into a very compact duplexer, designed using efficient numerical algorithms. The manufacturing process by mean of high precision milling, and including electrical discharge machining (EDM) has led to excellent performances. The measured return loss level and isolation are higher than 30 dB, and the insertion loss level is below 0.3 dB. Finally, the key parameter in this device, which reflects the symmetry in the manufacturing process, i.e., the axial ratio, is lower than 0.6 dB for both polarizations, an excellent result showing the potential of the presented design.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work presents the design and experimental validation of a high performance, compact, waveguide duplexer operating from 91.5 to 96.5 GHz for its integration in diverse W-band microwave equipment as in plasma diagnosis applications. It uses a single frequency band, with two signals discriminated by different orthogonal circular polarization, which is generated by means of a septum orthomode transducer (OMT) polarizer. Moreover, this component is optimized loaded with the horn antenna for improving the overall system performance. It is explained how these two components are integrated into a very compact duplexer, designed using efficient numerical algorithms. The manufacturing process by mean of high precision milling, and including electrical discharge machining (EDM) has led to excellent performances. The measured return loss level and isolation are higher than 30 dB, and the insertion loss level is below 0.3 dB. Finally, the key parameter in this device, which reflects the symmetry in the manufacturing process, i.e., the axial ratio, is lower than 0.6 dB for both polarizations, an excellent result showing the potential of the presented design. |
Martinez-de-Rioja, Eduardo; Martinez-de-Rioja, Daniel; Encinar, Jose A; Pino, Antonio; Gonzalez-Valdes, Borja; Rodriguez-Vaqueiro, Yolanda; Arias, Marcos; Toso, Giovanni Advanced Multibeam Antenna Configurations Based on Reflectarrays: Providing multispot coverage with a smaller number of apertures for satellite communications in the K and Ka bands Artículo de revista IEEE ANTENNAS AND PROPAGATION MAGAZINE, 61 (5), pp. 77-86, 2019, ISSN: 1045-9243. @article{MartinezdeRioja2019, title = {Advanced Multibeam Antenna Configurations Based on Reflectarrays: Providing multispot coverage with a smaller number of apertures for satellite communications in the K and Ka bands}, author = {Eduardo Martinez-de-Rioja and Daniel Martinez-de-Rioja and Jose A Encinar and Antonio Pino and Borja Gonzalez-Valdes and Yolanda Rodriguez-Vaqueiro and Marcos Arias and Giovanni Toso}, doi = {10.1109/MAP.2019.2932311}, issn = {1045-9243}, year = {2019}, date = {2019-10-01}, journal = {IEEE ANTENNAS AND PROPAGATION MAGAZINE}, volume = {61}, number = {5}, pages = {77-86}, abstract = {This article presents some recent developments in multiplebeam antennas (MBAs) based on reflectarrays for communication satellites in the Kurz (K) and Kurz-above (Ka) bands. The existing high-throughput satellites commonly employ four reflector antennas to provide cellular coverage that is formed by multiple spot beams in a four-color scheme. Reflectarray antennas are proposed as an attractive solution for the design of novel MBA configurations to produce multispot coverage, with a smaller number of apertures than conventional MBA systems based on reflector technology. Single and dual reflectarray configurations have been considered for the purpose of exploiting their ability to produce independent beams in different polarizations and frequencies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article presents some recent developments in multiplebeam antennas (MBAs) based on reflectarrays for communication satellites in the Kurz (K) and Kurz-above (Ka) bands. The existing high-throughput satellites commonly employ four reflector antennas to provide cellular coverage that is formed by multiple spot beams in a four-color scheme. Reflectarray antennas are proposed as an attractive solution for the design of novel MBA configurations to produce multispot coverage, with a smaller number of apertures than conventional MBA systems based on reflector technology. Single and dual reflectarray configurations have been considered for the purpose of exploiting their ability to produce independent beams in different polarizations and frequencies. |
Gonzalez-Calvo, Miguel; Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Additive Manufacturing of a High-Performance Q-Band Circular TE01 Mode Flared-Type Transducer Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 29 (9), pp. 577-579, 2019, ISSN: 1531-1309. @article{GonzalezCalvo2019, title = {Additive Manufacturing of a High-Performance Q-Band Circular TE01 Mode Flared-Type Transducer}, author = {Miguel Gonzalez-Calvo and Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1109/LMWC.2019.2927842}, issn = {1531-1309}, year = {2019}, date = {2019-09-01}, journal = {IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS}, volume = {29}, number = {9}, pages = {577-579}, abstract = {This letter presents a Q-band mode transducer based on a slowly flared structure to convert the rectangular TE10 mode into the circular TE01 mode, with an excellent performance in return loss level and conversion purity, overcoming the main issues of this kind of structures: its manufacturing complexity and high cost. They have been tackled by means of the additive manufacturing technology using selective laser sintering, especially well-suited for this problem allowing a single part suitable for high-power applications. The prototype shows a minimum return loss level of 20 dB in the whole Q-band. Measurements have been carried out using four different angles to connect two equal transducers in a back-to-back configuration (0 degrees, 45 degrees, 90 degrees, and 180 degrees). Furthermore, in spite of the expected roughness of the laser sintering, a measured converting efficiency higher than 82% in a 41% relative frequency bandwidth has been achieved. Therefore, the experimental results validate both the proposed geometry and the technology used for its implementation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This letter presents a Q-band mode transducer based on a slowly flared structure to convert the rectangular TE10 mode into the circular TE01 mode, with an excellent performance in return loss level and conversion purity, overcoming the main issues of this kind of structures: its manufacturing complexity and high cost. They have been tackled by means of the additive manufacturing technology using selective laser sintering, especially well-suited for this problem allowing a single part suitable for high-power applications. The prototype shows a minimum return loss level of 20 dB in the whole Q-band. Measurements have been carried out using four different angles to connect two equal transducers in a back-to-back configuration (0 degrees, 45 degrees, 90 degrees, and 180 degrees). Furthermore, in spite of the expected roughness of the laser sintering, a measured converting efficiency higher than 82% in a 41% relative frequency bandwidth has been achieved. Therefore, the experimental results validate both the proposed geometry and the technology used for its implementation. |
Moran-Lopez, Ana; Ruiz-Cruz, Jorge A; Corcoles, Juan; Montejo-Garai, Jose R; Rebollar, Jesus M Analytical expressions of the Q-factor for the complete resonant mode spectrum of the equilateral triangular waveguide cavity Artículo de revista ELECTRONICS LETTERS, 55 (17), pp. 944-946, 2019, ISSN: 0013-5194. @article{MoranLopez2019, title = {Analytical expressions of the Q-factor for the complete resonant mode spectrum of the equilateral triangular waveguide cavity}, author = {Ana Moran-Lopez and Jorge A Ruiz-Cruz and Juan Corcoles and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.1049/el.2019.1420}, issn = {0013-5194}, year = {2019}, date = {2019-08-01}, journal = {ELECTRONICS LETTERS}, volume = {55}, number = {17}, pages = {944-946}, abstract = {This Letter presents the closed-form expressions of the unloaded Q-factor in metallic cavities with equilateral triangular cross section, computed from its analytical resonant mode solutions. The obtained analytical formulas for the Q-factor extend the very restricted range of problems with closed-form solutions, complementing the classic cases of the rectangular and circular cavities found in the literature. The presented derivation provides extremely rapid reference solutions for diverse applications such as filter design by test cases for microwave characterisation systems or numerical full-wave solvers. A universal Q-chart, valid for any aspect ratio, is given and the achieved analytical results for the first resonant modes are tested with numerical commercial software, showing excellent agreement.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This Letter presents the closed-form expressions of the unloaded Q-factor in metallic cavities with equilateral triangular cross section, computed from its analytical resonant mode solutions. The obtained analytical formulas for the Q-factor extend the very restricted range of problems with closed-form solutions, complementing the classic cases of the rectangular and circular cavities found in the literature. The presented derivation provides extremely rapid reference solutions for diverse applications such as filter design by test cases for microwave characterisation systems or numerical full-wave solvers. A universal Q-chart, valid for any aspect ratio, is given and the achieved analytical results for the first resonant modes are tested with numerical commercial software, showing excellent agreement. |
Martinez-de-Rioja, Daniel; Florencio, Rafael; Encinar, Jose A; Carrasco, Eduardo; Boix, Rafael R Dual-Frequency Reflectarray Cell to Provide Opposite Phase Shift in Dual Circular Polarization With Application in Multibeam Satellite Antennas Artículo de revista IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, 18 (8), pp. 1591-1595, 2019, ISSN: 1536-1225. @article{MartinezdeRioja2019a, title = {Dual-Frequency Reflectarray Cell to Provide Opposite Phase Shift in Dual Circular Polarization With Application in Multibeam Satellite Antennas}, author = {Daniel Martinez-de-Rioja and Rafael Florencio and Jose A Encinar and Eduardo Carrasco and Rafael R Boix}, doi = {10.1109/LAWP.2019.2924354}, issn = {1536-1225}, year = {2019}, date = {2019-08-01}, journal = {IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS}, volume = {18}, number = {8}, pages = {1591-1595}, abstract = {A new reflectarray cell is proposed to simultaneously provide opposite phase shifts between orthogonal circular polarizations at two frequencies (19.7 and 29.5 GHz) by applying a variable rotation technique independently at each frequency. The reflectarray cell, which consists of two dielectric layers with two levels of printed elements (dipoles and arcs), has been characterized for both circular and linear polarizations at each frequency. Apart from the implementation of the variable rotation technique at each frequency, the reflectarray cell provides an additional phase adjustment at the higher frequency, which can be used to shape the beam. This concept applied to multiple spot satellites in Ka-band will allow to produce two adjacent beams per feed in orthogonal circular polarizations at transmission and reception frequency bands.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new reflectarray cell is proposed to simultaneously provide opposite phase shifts between orthogonal circular polarizations at two frequencies (19.7 and 29.5 GHz) by applying a variable rotation technique independently at each frequency. The reflectarray cell, which consists of two dielectric layers with two levels of printed elements (dipoles and arcs), has been characterized for both circular and linear polarizations at each frequency. Apart from the implementation of the variable rotation technique at each frequency, the reflectarray cell provides an additional phase adjustment at the higher frequency, which can be used to shape the beam. This concept applied to multiple spot satellites in Ka-band will allow to produce two adjacent beams per feed in orthogonal circular polarizations at transmission and reception frequency bands. |
Somolinos, Alvaro; Florencio, Rafael; Gonzalez, Ivan; Encinar, Jose A; Catedra, Felipe Experimental Validation of Generating Two Spaced Beams With Reflectarrays by VRT Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (6), pp. 4263-4268, 2019, ISSN: 0018-926X. @article{Somolinos2019, title = {Experimental Validation of Generating Two Spaced Beams With Reflectarrays by VRT}, author = {Alvaro Somolinos and Rafael Florencio and Ivan Gonzalez and Jose A Encinar and Felipe Catedra}, doi = {10.1109/TAP.2019.2907862}, issn = {0018-926X}, year = {2019}, date = {2019-06-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {6}, pages = {4263-4268}, abstract = {The concept of generating two spaced beams in dual-CP by variable rotation technique (VRT) is validated for the first time by manufacturing and measuring. A reflectarray demonstrator has been designed, manufactured, and tested to deviate +/- 10 degrees the beam of a dual-CP multiflared horn at 19.7 GHz. The proposed reflectarray cell for VRT is made of a conductive cross printed on a grounded dielectric. The experimental results show that two adjacent beams in dual-CP maintain the correct directions in the prescribed frequency band (19.2-20.2 GHz). The results are satisfactory and validate the concept for generating two spaced beams in orthogonal CP by VRT with a single feed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The concept of generating two spaced beams in dual-CP by variable rotation technique (VRT) is validated for the first time by manufacturing and measuring. A reflectarray demonstrator has been designed, manufactured, and tested to deviate +/- 10 degrees the beam of a dual-CP multiflared horn at 19.7 GHz. The proposed reflectarray cell for VRT is made of a conductive cross printed on a grounded dielectric. The experimental results show that two adjacent beams in dual-CP maintain the correct directions in the prescribed frequency band (19.2-20.2 GHz). The results are satisfactory and validate the concept for generating two spaced beams in orthogonal CP by VRT with a single feed. |
Florencio, Rafael; Encinar, Jose A; Boix, Rafael R; Barba, Mariano; Toso, Giovanni Flat Reflectarray That Generates Adjacent Beams by Discriminating in Dual Circular Polarization Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (6), pp. 3733-3742, 2019, ISSN: 0018-926X. @article{Florencio2019, title = {Flat Reflectarray That Generates Adjacent Beams by Discriminating in Dual Circular Polarization}, author = {Rafael Florencio and Jose A Encinar and Rafael R Boix and Mariano Barba and Giovanni Toso}, doi = {10.1109/TAP.2019.2905676}, issn = {0018-926X}, year = {2019}, date = {2019-06-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {6}, pages = {3733-3742}, abstract = {One planar 18 x 18 cm(2) reflectarray prototype, capable of generating adjacent pencil beams with the orthogonal circular polarizations (CPs) in the Ka-band (19.2-20.2 GHz), has been designed, manufactured, and measured as a proof-of-concept to demonstrate the possibility of beam separation in the dual-CP applications. The prototype exhibits main beams pointing at elevation angles of 16.7 degrees and 21.3 degrees for left-hand CP and right-hand CP, respectively. A 1.5 dB gain variation and 66% of efficiency are achieved in the frequency band 19.2-20.2 GHz for a design center frequency of 19.7 GHz. These results will be useful for the future work, involving the design of multispot dual-CP and dual-band planar reflectarrays.}, keywords = {}, pubstate = {published}, tppubtype = {article} } One planar 18 x 18 cm(2) reflectarray prototype, capable of generating adjacent pencil beams with the orthogonal circular polarizations (CPs) in the Ka-band (19.2-20.2 GHz), has been designed, manufactured, and measured as a proof-of-concept to demonstrate the possibility of beam separation in the dual-CP applications. The prototype exhibits main beams pointing at elevation angles of 16.7 degrees and 21.3 degrees for left-hand CP and right-hand CP, respectively. A 1.5 dB gain variation and 66% of efficiency are achieved in the frequency band 19.2-20.2 GHz for a design center frequency of 19.7 GHz. These results will be useful for the future work, involving the design of multispot dual-CP and dual-band planar reflectarrays. |
Carrasco, Eduardo; Colombi, D; Foster, K R; Ziskin, M; Balzano, Q EXPOSURE ASSESSMENT OF PORTABLE WIRELESS DEVICES ABOVE 6 GHZ Artículo de revista RADIATION PROTECTION DOSIMETRY, 183 (4), pp. 489-496, 2019, ISSN: 0144-8420. @article{ISI:000489284800011, title = {EXPOSURE ASSESSMENT OF PORTABLE WIRELESS DEVICES ABOVE 6 GHZ}, author = {Eduardo Carrasco and D Colombi and K R Foster and M Ziskin and Q Balzano}, doi = {10.1093/rpd/ncy177}, issn = {0144-8420}, year = {2019}, date = {2019-06-01}, journal = {RADIATION PROTECTION DOSIMETRY}, volume = {183}, number = {4}, pages = {489-496}, abstract = {The emerging 5 G wireless devices working at frequencies above 6 GHz are expected to have antenna arrays formed by dipoles, slots, patches or their combination. At lower frequencies, the accepted criteria for exposure compliance is stated in terms of specific absorption rate. IEEE and ICNIRP are adopting epithelial or transmitted power density (PD through body surface) as the dosimetric reference for frequencies above 6 GHz, which entails the measurement of free space PD. Theoretical and numerical results presented in this article show that it is possible to perform meaningful free space PD assessments at half wave (lambda/2) distance from arrays and, with the proper instrumentation, as close as lambda/(2 pi). However, if a dissipative body is placed very close ( relevance of such an effect should be further investigated, for instance by means of experimental analysis including measurements of tissue heating when in the presence of a strong reactive near field.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The emerging 5 G wireless devices working at frequencies above 6 GHz are expected to have antenna arrays formed by dipoles, slots, patches or their combination. At lower frequencies, the accepted criteria for exposure compliance is stated in terms of specific absorption rate. IEEE and ICNIRP are adopting epithelial or transmitted power density (PD through body surface) as the dosimetric reference for frequencies above 6 GHz, which entails the measurement of free space PD. Theoretical and numerical results presented in this article show that it is possible to perform meaningful free space PD assessments at half wave (lambda/2) distance from arrays and, with the proper instrumentation, as close as lambda/(2 pi). However, if a dissipative body is placed very close (<lambda/2 pi) to the arrays, its reflection and absorption of RF energy can change the electric currents and charges over the antenna. The relevance of such an effect should be further investigated, for instance by means of experimental analysis including measurements of tissue heating when in the presence of a strong reactive near field. |
Polo-Lopez, Lucas; Corcoles, Juan; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M On the Theoretical Maximum Directivity of a Radiating Aperture From Modal Field Expansions Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (4, 2), pp. 2781-2786, 2019, ISSN: 0018-926X. @article{PoloLopez2019, title = {On the Theoretical Maximum Directivity of a Radiating Aperture From Modal Field Expansions}, author = {Lucas Polo-Lopez and Juan Corcoles and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.1109/TAP.2019.2896660}, issn = {0018-926X}, year = {2019}, date = {2019-04-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {4, 2}, pages = {2781-2786}, abstract = {This communication addresses the maximization of the directivity from a radiating aperture through the derivation of a closed-form expression for the modal field amplitudes whose field distribution at the aperture maximizes the directivity in a desired direction. This closed-form expression arises from a convex formulation of the maximization problem (as a ratio of two Hermitian forms), which mathematically ensures that the achieved directivity value is the global maximum for a specified number of propagating modes. The proposed technique, which is valid for any aperture shape and polarization, is discussed and compared with previous work. Several numerical examples considering different main lobe directions, aperture geometries, and polarizations are presented. To verify the numerical results, radiation patterns and directivity values are computed using both commercial tools and in-house developed software.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This communication addresses the maximization of the directivity from a radiating aperture through the derivation of a closed-form expression for the modal field amplitudes whose field distribution at the aperture maximizes the directivity in a desired direction. This closed-form expression arises from a convex formulation of the maximization problem (as a ratio of two Hermitian forms), which mathematically ensures that the achieved directivity value is the global maximum for a specified number of propagating modes. The proposed technique, which is valid for any aperture shape and polarization, is discussed and compared with previous work. Several numerical examples considering different main lobe directions, aperture geometries, and polarizations are presented. To verify the numerical results, radiation patterns and directivity values are computed using both commercial tools and in-house developed software. |
Pfeifer, S; Carrasco, Eduardo; Crespo-Valero, P; Neufeld, E; Kuhn, S; Samaras, T; Christ, A; Capstick, M H; Kuster, N Total Field Reconstruction in the Near Field Using Pseudo-Vector E-Field Measurements Artículo de revista IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, 61 (2), pp. 476-486, 2019, ISSN: 0018-9375. @article{ISI:000457790400019, title = {Total Field Reconstruction in the Near Field Using Pseudo-Vector E-Field Measurements}, author = {S Pfeifer and Eduardo Carrasco and P Crespo-Valero and E Neufeld and S Kuhn and T Samaras and A Christ and M H Capstick and N Kuster}, doi = {10.1109/TEMC.2018.2837897}, issn = {0018-9375}, year = {2019}, date = {2019-04-01}, journal = {IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY}, volume = {61}, number = {2}, pages = {476-486}, abstract = {Exposure assessments in the frequency range above 10 GHz typically require knowledge of the power density very close to the radiator (at 2-mm distance), which can be obtained through the total electric and magnetic fields. However, phase measurements are often not feasible in this frequency range, in particular in the reactive near field. We developed a novel phase reconstruction approach based on plane-to-plane reconstruction algorithms. It uses E- field polarization ellipse information, which can be obtained extremely close to the source with probes based on the pseudo-vector sensor design. The algorithm's robustness and accuracy were analyzed and optimized for distances of a fraction of the wavelength., and a comprehensive set of realistic exposure conditions was simulated to evaluate the algorithm. For distances greater than lambda/ 5, the error of the spatially averaged peak incident power density is found to be below 0.5 dB. Measurements in four different antenna prototypes revealed that the simulated deviation of reconstructed averaged power density was consistently below 1.1 dB for distances as close as 2 mm, i.e., smaller than the estimated total experimental assessment uncertainty of 1.4 dB. This demonstrates that the power density can be reliably determined by measurements as close as lambda/5 from any transmitter.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Exposure assessments in the frequency range above 10 GHz typically require knowledge of the power density very close to the radiator (at 2-mm distance), which can be obtained through the total electric and magnetic fields. However, phase measurements are often not feasible in this frequency range, in particular in the reactive near field. We developed a novel phase reconstruction approach based on plane-to-plane reconstruction algorithms. It uses E- field polarization ellipse information, which can be obtained extremely close to the source with probes based on the pseudo-vector sensor design. The algorithm's robustness and accuracy were analyzed and optimized for distances of a fraction of the wavelength., and a comprehensive set of realistic exposure conditions was simulated to evaluate the algorithm. For distances greater than lambda/ 5, the error of the spatially averaged peak incident power density is found to be below 0.5 dB. Measurements in four different antenna prototypes revealed that the simulated deviation of reconstructed averaged power density was consistently below 1.1 dB for distances as close as 2 mm, i.e., smaller than the estimated total experimental assessment uncertainty of 1.4 dB. This demonstrates that the power density can be reliably determined by measurements as close as lambda/5 from any transmitter. |
Florencio, Rafael; Boix, Rafael R; Encinar, Jose A Efficient Spectral Domain MoM for the Design of Circularly Polarized Reflectarray Antennas Made of Split Rings Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (3), pp. 1760-1771, 2019, ISSN: 0018-926X. @article{Florencio2019a, title = {Efficient Spectral Domain MoM for the Design of Circularly Polarized Reflectarray Antennas Made of Split Rings}, author = {Rafael Florencio and Rafael R Boix and Jose A Encinar}, doi = {10.1109/TAP.2018.2888956}, issn = {0018-926X}, year = {2019}, date = {2019-03-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {3}, pages = {1760-1771}, abstract = {The method of moments (MoM) in the spectral domain is used for the analysis of the scattering of a plane wave by a multilayered periodic structure containing conducting concentric split rings in the unit cell. Basis functions accounting for edge singularities are used in the approximation of the current density on the split rings, which makes it possible a fast convergence of MoM with respect to the number of basis functions. Since the 2-D Fourier transforms of the basis functions cannot be obtained in closed-form, judicious tricks (controlled truncation of infinite summations, interpolations, etc.) are used for the efficient numerical determination of these Fourier transforms. The implemented spectral domain MoM software has been used in the design of a circularly polarized reflectarray antenna based on split rings under the local periodicity condition. The antenna has been analyzed with our spectral domain MoM software, with CST and with HFSS, and good agreement has been found among all sets of results. Our software has proven to be around 27 times faster than CST and HFSS.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The method of moments (MoM) in the spectral domain is used for the analysis of the scattering of a plane wave by a multilayered periodic structure containing conducting concentric split rings in the unit cell. Basis functions accounting for edge singularities are used in the approximation of the current density on the split rings, which makes it possible a fast convergence of MoM with respect to the number of basis functions. Since the 2-D Fourier transforms of the basis functions cannot be obtained in closed-form, judicious tricks (controlled truncation of infinite summations, interpolations, etc.) are used for the efficient numerical determination of these Fourier transforms. The implemented spectral domain MoM software has been used in the design of a circularly polarized reflectarray antenna based on split rings under the local periodicity condition. The antenna has been analyzed with our spectral domain MoM software, with CST and with HFSS, and good agreement has been found among all sets of results. Our software has proven to be around 27 times faster than CST and HFSS. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Encinar, Jose A; Florencio, Rafael; Toso, Giovanni Reflectarray to Generate Four Adjacent Beams per Feed for Multispot Satellite Antennas Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (2), pp. 1265-1269, 2019, ISSN: 0018-926X. @article{MartinezdeRioja2019b, title = {Reflectarray to Generate Four Adjacent Beams per Feed for Multispot Satellite Antennas}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Jose A Encinar and Rafael Florencio and Giovanni Toso}, doi = {10.1109/TAP.2018.2880117}, issn = {0018-926X}, year = {2019}, date = {2019-02-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {2}, pages = {1265-1269}, abstract = {This contribution describes a design concept of a reflectarray antenna to produce four adjacent beams per feed through the simultaneous use of polarization and frequency discrimination. The feed position is computed to produce two adjacent beams in different frequencies accounting for the beam squint effect, which ensures a minimum phase variation between the phase distributions at the two frequencies. The other two beams in orthogonal polarization are generated by implementing in the reflectarray a different phase shift for each polarization. This contribution presents the design, manufacturing, and measurement of a 43 cm demonstrator that operates at transmit frequencies in the Ka-band. The proposed concept can be suitable for multiple spot-beam satellites in the Ka-band, enabling a reduction in the number of antennas and feeds needed to provide the multispot coverage.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This contribution describes a design concept of a reflectarray antenna to produce four adjacent beams per feed through the simultaneous use of polarization and frequency discrimination. The feed position is computed to produce two adjacent beams in different frequencies accounting for the beam squint effect, which ensures a minimum phase variation between the phase distributions at the two frequencies. The other two beams in orthogonal polarization are generated by implementing in the reflectarray a different phase shift for each polarization. This contribution presents the design, manufacturing, and measurement of a 43 cm demonstrator that operates at transmit frequencies in the Ka-band. The proposed concept can be suitable for multiple spot-beam satellites in the Ka-band, enabling a reduction in the number of antennas and feeds needed to provide the multispot coverage. |
Buesa-Zubiria, Ana María; Pérez-Palomino, Gerardo; Conde-Pumpido, Fernando; Martínez-de-Rioja, Eduardo; Martínez-de-Rioja, Daniel; Montejo-Garai, Jose R; Carrasco, Eduardo; Encinar, Jose A; García, Jesus; Lambea-Olgado, Manuel; Gil, Jose M Problemas de Introducción al Análisis de Circuitos (plan 2010) Libro Fundetel, ETSIT-UPM, 2019, ISBN: 978-84-7402-427-2. @book{, title = {Problemas de Introducción al Análisis de Circuitos (plan 2010)}, author = {Ana María Buesa-Zubiria and Gerardo Pérez-Palomino and Fernando Conde-Pumpido and Eduardo Martínez-de-Rioja and Daniel Martínez-de-Rioja and Jose R Montejo-Garai and Eduardo Carrasco and Jose A Encinar and Jesus García and Manuel Lambea-Olgado and Jose M Gil}, isbn = {978-84-7402-427-2}, year = {2019}, date = {2019-01-01}, publisher = {Fundetel, ETSIT-UPM}, keywords = {}, pubstate = {published}, tppubtype = {book} } |
Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M Design of a Ku-Band High-Purity Transducer for the TM01 Circular Waveguide Mode by Means of T-Type Junctions Artículo de revista IEEE ACCESS, 7 , pp. 450-456, 2019, ISSN: 2169-3536. @article{MontejoGarai2019b, title = {Design of a Ku-Band High-Purity Transducer for the TM01 Circular Waveguide Mode by Means of T-Type Junctions}, author = {Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1109/ACCESS.2018.2885489}, issn = {2169-3536}, year = {2019}, date = {2019-01-01}, journal = {IEEE ACCESS}, volume = {7}, pages = {450-456}, abstract = {A new mode transducer for converting the TE10 rectangular waveguide mode to the TM01 circular waveguide mode is presented. The novel topology is based on two T-type junctions with in-phase excitation at their input rectangular ports. The first one is an H-plane T-junction in rectangular waveguide. The second one differs from the standard E-plane T-junction in the excitation, which is carried out by modes excited with fields having the same in-phase polarization at the input rectangular ports, and has the output port in circular waveguide. This configuration exploits the symmetry of the modes under consideration to achieve a high-purity conversion, controlling the propagating circular waveguide TE11 mode to a maximum level of -42 dB in the whole operation band. The design bandwidth is 2 GHz centered at 12 GHz with a return loss level higher than 28 dB. In addition, the transducer can be divided in a main body plus a cover for easing the manufacturing. In order to verify the proposed geometry, a back-to-back arrangement has been measured connecting two similar aluminum transducers with four different angles between their rectangular ports (0 degrees, 45 degrees, 90 degrees, and 180 degrees). The excellent experimental results validate the novel transducer with a measured converting efficiency higher than 98.2% in a 16.7% relative frequency bandwidth.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new mode transducer for converting the TE10 rectangular waveguide mode to the TM01 circular waveguide mode is presented. The novel topology is based on two T-type junctions with in-phase excitation at their input rectangular ports. The first one is an H-plane T-junction in rectangular waveguide. The second one differs from the standard E-plane T-junction in the excitation, which is carried out by modes excited with fields having the same in-phase polarization at the input rectangular ports, and has the output port in circular waveguide. This configuration exploits the symmetry of the modes under consideration to achieve a high-purity conversion, controlling the propagating circular waveguide TE11 mode to a maximum level of -42 dB in the whole operation band. The design bandwidth is 2 GHz centered at 12 GHz with a return loss level higher than 28 dB. In addition, the transducer can be divided in a main body plus a cover for easing the manufacturing. In order to verify the proposed geometry, a back-to-back arrangement has been measured connecting two similar aluminum transducers with four different angles between their rectangular ports (0 degrees, 45 degrees, 90 degrees, and 180 degrees). The excellent experimental results validate the novel transducer with a measured converting efficiency higher than 98.2% in a 16.7% relative frequency bandwidth. |
Haro-Baez, Raul V; Corcoles, Juan; Ruiz-Cruz, Jorge A; Montejo-Garai, Jose R; Rebollar, Jesus M Higher-Order Mode Electromagnetic Analysis of a Material Sample between Two Flanged Coaxial Probes for Broadband Modelling of Dielectric Measurement Setups Artículo de revista ADVANCES IN MATHEMATICAL PHYSICS, 2019 , 2019, ISSN: 1687-9120. @article{HaroBaez2019, title = {Higher-Order Mode Electromagnetic Analysis of a Material Sample between Two Flanged Coaxial Probes for Broadband Modelling of Dielectric Measurement Setups}, author = {Raul V Haro-Baez and Juan Corcoles and Jorge A Ruiz-Cruz and Jose R Montejo-Garai and Jesus M Rebollar}, doi = {10.1155/2019/6404812}, issn = {1687-9120}, year = {2019}, date = {2019-01-01}, journal = {ADVANCES IN MATHEMATICAL PHYSICS}, volume = {2019}, abstract = {The characterization of the dielectric properties of a material requires a measurement technique and its associated analysis method. In this work, the configuration involving two coaxial probes with a material for dielectric measurement between them is analyzed with a mode-matching approach. To that effect, two models with different complexity and particularities are proposed. It will be shown how convergence is sped up for accurate results by using a proper choice of higher-order modes along with a combination of perfect electric wall and perfect magnetic wall boundary conditions. It will also be shown how the frequency response is affected by the flange mounting size, which can be, rigorously and efficiently, taken into account with the same type of approach. This numerical study is validated through a wide range of simulations with reference values from another method, showing how the proposed approaches can be used for the broadband characterization of this well-known, but with a recent renewed interest from the research community, dielectric measurement setup.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The characterization of the dielectric properties of a material requires a measurement technique and its associated analysis method. In this work, the configuration involving two coaxial probes with a material for dielectric measurement between them is analyzed with a mode-matching approach. To that effect, two models with different complexity and particularities are proposed. It will be shown how convergence is sped up for accurate results by using a proper choice of higher-order modes along with a combination of perfect electric wall and perfect magnetic wall boundary conditions. It will also be shown how the frequency response is affected by the flange mounting size, which can be, rigorously and efficiently, taken into account with the same type of approach. This numerical study is validated through a wide range of simulations with reference values from another method, showing how the proposed approaches can be used for the broadband characterization of this well-known, but with a recent renewed interest from the research community, dielectric measurement setup. |
Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M A 10-Way Power Divider Based on a Transducer and a Radial Junction Operating in the Circular TM01 Mode Artículo de revista IEEE ACCESS, 7 , pp. 127353-127361, 2019, ISSN: 2169-3536. @article{MontejoGarai2019a, title = {A 10-Way Power Divider Based on a Transducer and a Radial Junction Operating in the Circular TM01 Mode}, author = {Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1109/ACCESS.2019.2939291}, issn = {2169-3536}, year = {2019}, date = {2019-01-01}, journal = {IEEE ACCESS}, volume = {7}, pages = {127353-127361}, abstract = {This work presents a 10-way Ku-band power divider using a mode transducer and a radial junction connected by an overmoded circular waveguide operating in the TM01 mode. The circular symmetry of this mode has been exploited to obtain a power divider with the rectangular output ports radially distributed along the broad wall of the waveguides in H-plane configuration. This topology provides the same amplitude and phase for all the output ports. At the same time, a compact profile has been obtained, introducing a simple manufacturing for the two components of the divider. The first component is a mode transducer converting the TE10 mode in the rectangular waveguide to the TM01 mode in the circular waveguide. It is based on a novel topology providing a very high purity in the mode conversion with an attenuation for the other propagating mode, the TE11c, higher than 60 dB. The second component is a 10-way radial junction that must work under the excitation of the TM01, whose special features, since this mode is not the fundamental one of the circular waveguide, will be highlighted. The final design has been validated with an experimental prototype, proposing a manufacturing based on four simple parts. This has been the key to obtain an experimental prototype with specifications in the state-of-the-art. The measured efficiency is better than 96.5% in a 16.7% relative frequency bandwidth from 11 GHz to 13 GHz, with return losses better than 25 dB in the common port. The measured difference between the signals at the output ports of the prototype is +/- 0.3 dB for the amplitudes and +/- 0.45 degrees for the phases. A comparison of the obtained results with another divider based on the TE01 mode shows the potential of the presented design for becoming an alternative to the more extended TE01-based power dividers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work presents a 10-way Ku-band power divider using a mode transducer and a radial junction connected by an overmoded circular waveguide operating in the TM01 mode. The circular symmetry of this mode has been exploited to obtain a power divider with the rectangular output ports radially distributed along the broad wall of the waveguides in H-plane configuration. This topology provides the same amplitude and phase for all the output ports. At the same time, a compact profile has been obtained, introducing a simple manufacturing for the two components of the divider. The first component is a mode transducer converting the TE10 mode in the rectangular waveguide to the TM01 mode in the circular waveguide. It is based on a novel topology providing a very high purity in the mode conversion with an attenuation for the other propagating mode, the TE11c, higher than 60 dB. The second component is a 10-way radial junction that must work under the excitation of the TM01, whose special features, since this mode is not the fundamental one of the circular waveguide, will be highlighted. The final design has been validated with an experimental prototype, proposing a manufacturing based on four simple parts. This has been the key to obtain an experimental prototype with specifications in the state-of-the-art. The measured efficiency is better than 96.5% in a 16.7% relative frequency bandwidth from 11 GHz to 13 GHz, with return losses better than 25 dB in the common port. The measured difference between the signals at the output ports of the prototype is +/- 0.3 dB for the amplitudes and +/- 0.45 degrees for the phases. A comparison of the obtained results with another divider based on the TE01 mode shows the potential of the presented design for becoming an alternative to the more extended TE01-based power dividers. |
Rubio, Jesus; Gomez, Alfonso; Gomez, Rafael; Garcia, Jesus; Campos-Roca, Yolanda; Gil, Jose M; Gonzalez-de-Aza, Miguel A Fast Anaysis of Arrays of Antennas Fed by Substrate Integrated Waveguides Artículo en actas Cracovia, Poland, 2019. @inproceedings{Rubio2019, title = {Fast Anaysis of Arrays of Antennas Fed by Substrate Integrated Waveguides}, author = {Jesus Rubio and Alfonso Gomez and Rafael Gomez and Jesus Garcia and Yolanda Campos-Roca and Jose M Gil and Miguel A Gonzalez-de-Aza}, year = {2019}, date = {2019-01-01}, address = {Cracovia, Poland}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Garcia, Alfonso Gomez; Gonzalez-de-Aza, Miguel A; Alcala, Rafael Gomez; Garcia, Jesus; Campos-Roca, Yolanda; Gil, Jose M; Rubio, Jesus Applications of the direct domain decomposition based on cylindrical ports in the hybrid Finite Element/Modal Analysis method Artículo en actas pp. 0124–0128, IEEE, Granada, Spain, 2019, ISBN: 978-1-7281-0564-2. @inproceedings{Garcia2019a, title = {Applications of the direct domain decomposition based on cylindrical ports in the hybrid Finite Element/Modal Analysis method}, author = {Alfonso Gomez Garcia and Miguel A Gonzalez-de-Aza and Rafael Gomez Alcala and Jesus Garcia and Yolanda Campos-Roca and Jose M Gil and Jesus Rubio}, doi = {10.1109/ICEAA.2019.8879007}, isbn = {978-1-7281-0564-2}, year = {2019}, date = {2019-01-01}, pages = {0124--0128}, publisher = {IEEE}, address = {Granada, Spain}, abstract = {In this work, it will be shown some interesting capabilities of a direct domain decomposition methodology, based on the use of the hybrid finite element/modal analysis (FE/MA), which takes advantage of the addition theorems for cylindrical waves. These theorems allow to perform analytical rotations and translations of domains in the whole structure, avoiding recalculations with the FE/MA method. Specifically, it will be used to place via holes between patch antennas on a continuous substrate, in order to prevent mutual coupling through the substrate. It will also be shown how this methodology can be applied to the fast analysis of radial line slot antennas, where each slot is considered as a subdomain defined by a cylindrical port and a hemispherical port; and to the analysis of groove gap waveguides, where each quadrangular post is characterized by a cylindrical port.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } In this work, it will be shown some interesting capabilities of a direct domain decomposition methodology, based on the use of the hybrid finite element/modal analysis (FE/MA), which takes advantage of the addition theorems for cylindrical waves. These theorems allow to perform analytical rotations and translations of domains in the whole structure, avoiding recalculations with the FE/MA method. Specifically, it will be used to place via holes between patch antennas on a continuous substrate, in order to prevent mutual coupling through the substrate. It will also be shown how this methodology can be applied to the fast analysis of radial line slot antennas, where each slot is considered as a subdomain defined by a cylindrical port and a hemispherical port; and to the analysis of groove gap waveguides, where each quadrangular post is characterized by a cylindrical port. |
Gil, Jose M; Conde-Pumpido, Fernando; Gonzalez-de-Aza, Miguel A; Alcalá, Rafael Gómez; Garcia, Jesus; Rubio, Jesús; Garcia, Alfonso Gómez; Campos-Roca, Yolanda Decoupled Basis Function Subspaces for Dealing Low-frequency Discretization in the Combined Field Integral Equation Artículo en actas Potes, Cantabria, Spain, 2019. @inproceedings{Gil2019, title = {Decoupled Basis Function Subspaces for Dealing Low-frequency Discretization in the Combined Field Integral Equation}, author = {Jose M Gil and Fernando Conde-Pumpido and Miguel A Gonzalez-de-Aza and Rafael Gómez Alcalá and Jesus Garcia and Jesús Rubio and Alfonso Gómez Garcia and Yolanda Campos-Roca}, year = {2019}, date = {2019-01-01}, address = {Potes, Cantabria, Spain}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Garcia, Alfonso Gómez; Alcalá, Rafael Gómez; Garcia, Jesus; Gonzalez-de-Aza, Miguel A; Gil, Jose M; Rubio, Jesús; Campos-Roca, Yolanda A Design Method for waveguide circuits including arbitrary posts using radial waveguide modes scattering Artículo en actas Potes, Cantabria, Spain, 2019. @inproceedings{Garcia2019, title = {A Design Method for waveguide circuits including arbitrary posts using radial waveguide modes scattering}, author = {Alfonso Gómez Garcia and Rafael Gómez Alcalá and Jesus Garcia and Miguel A Gonzalez-de-Aza and Jose M Gil and Jesús Rubio and Yolanda Campos-Roca}, year = {2019}, date = {2019-01-01}, address = {Potes, Cantabria, Spain}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Alex-Amor, Antonio; Moreno-Núñez, Javier; Fernández-González, José M; Padilla, Pablo; Esteban, J Parasitics Impact on the Performance of Rectifier Circuits in Sensing RF Energy Harvesting Artículo de revista Sensors, 19 (22), pp. 4939, 2019, ISSN: 1424-8220. @article{AlexAmor2019a, title = {Parasitics Impact on the Performance of Rectifier Circuits in Sensing RF Energy Harvesting}, author = {Antonio Alex-Amor and Javier Moreno-Núñez and José M Fernández-González and Pablo Padilla and J Esteban}, url = {https://www.mdpi.com/1424-8220/19/22/4939}, doi = {10.3390/s19224939}, issn = {1424-8220}, year = {2019}, date = {2019-01-01}, journal = {Sensors}, volume = {19}, number = {22}, pages = {4939}, abstract = {This work presents some accurate guidelines for the design of rectifier circuits in radiofrequency (RF) energy harvesting. New light is shed on the design process, paying special attention to the nonlinearity of the circuits and the modeling of the parasitic elements. Two different configurations are tested: a Cockcroft–Walton multiplier and a half-wave rectifier. Several combinations of diodes, capacitors, inductors and loads were studied. Furthermore, the parasitics that are part of the circuits were modeled. Thus, the most harmful parasitics were identified and studied in depth in order to improve the conversion efficiency and enhance the performance of self-sustaining sensing systems. The experimental results show that the parasitics associated with the diode package and the via holes in the PCB (Printed Circuit Board) can leave the circuits inoperative. As an example, the rectifier efficiency is below 5% without considering the influence of the parasitics. On the other hand, it increases to over 30% in both circuits after considering them, twice the value of typical passive rectifiers}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work presents some accurate guidelines for the design of rectifier circuits in radiofrequency (RF) energy harvesting. New light is shed on the design process, paying special attention to the nonlinearity of the circuits and the modeling of the parasitic elements. Two different configurations are tested: a Cockcroft–Walton multiplier and a half-wave rectifier. Several combinations of diodes, capacitors, inductors and loads were studied. Furthermore, the parasitics that are part of the circuits were modeled. Thus, the most harmful parasitics were identified and studied in depth in order to improve the conversion efficiency and enhance the performance of self-sustaining sensing systems. The experimental results show that the parasitics associated with the diode package and the via holes in the PCB (Printed Circuit Board) can leave the circuits inoperative. As an example, the rectifier efficiency is below 5% without considering the influence of the parasitics. On the other hand, it increases to over 30% in both circuits after considering them, twice the value of typical passive rectifiers |
Alex-Amor, Antonio; Palomares-Caballero, Ángel; Fernández-González, José M; Padilla, Pablo; Marcos, David; Sierra-Castañer, Manuel; Esteban, J RF Energy Harvesting System Based on an Archimedean Spiral Antenna for Low-Power Sensor Applications Artículo de revista Sensors, 19 (6), pp. 1318, 2019, ISSN: 1424-8220. @article{AlexAmor2019, title = {RF Energy Harvesting System Based on an Archimedean Spiral Antenna for Low-Power Sensor Applications}, author = {Antonio Alex-Amor and Ángel Palomares-Caballero and José M Fernández-González and Pablo Padilla and David Marcos and Manuel Sierra-Castañer and J Esteban}, url = {http://www.mdpi.com/1424-8220/19/6/1318}, doi = {10.3390/s19061318}, issn = {1424-8220}, year = {2019}, date = {2019-01-01}, journal = {Sensors}, volume = {19}, number = {6}, pages = {1318}, abstract = {This paper presents a radiofrequency (RF) energy harvesting system based on an ultrawideband Archimedean spiral antenna and a half-wave Cockcroft-Walton multiplier circuit. The antenna was proved to operate from 350 MHz to 16 GHz with an outstanding performance. With its use, radio spectrum measurements were carried out at the Telecommunication Engineering School (Universidad Politécnica de Madrid) to determine the power level of the ambient signals in two different scenarios: indoors and outdoors. Based on these measurements, a Cockcroft-Walton multiplier and a lumped element matching network are designed to operate at 800 MHz and 900 MHz frequency bands. To correct the frequency displacement in the circuit, a circuit model is presented that takes into account the different parasitic elements of the components and the PCB. With an input power of 0 dBm, the manufactured circuit shows a rectifying efficiency of 30%. Finally, a test is carried out with the full RF energy harvesting system to check its correct operation. Thus, the RF system is placed in front of a transmitting Vivaldi antenna at a distance of 50 cm. The storage capacitor has a charge of over 1.25 V, which is enough to run a temperature sensor placed as the load to be supplied. This demonstrates the validity of the RF energy harvesting system for low-power practical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper presents a radiofrequency (RF) energy harvesting system based on an ultrawideband Archimedean spiral antenna and a half-wave Cockcroft-Walton multiplier circuit. The antenna was proved to operate from 350 MHz to 16 GHz with an outstanding performance. With its use, radio spectrum measurements were carried out at the Telecommunication Engineering School (Universidad Politécnica de Madrid) to determine the power level of the ambient signals in two different scenarios: indoors and outdoors. Based on these measurements, a Cockcroft-Walton multiplier and a lumped element matching network are designed to operate at 800 MHz and 900 MHz frequency bands. To correct the frequency displacement in the circuit, a circuit model is presented that takes into account the different parasitic elements of the components and the PCB. With an input power of 0 dBm, the manufactured circuit shows a rectifying efficiency of 30%. Finally, a test is carried out with the full RF energy harvesting system to check its correct operation. Thus, the RF system is placed in front of a transmitting Vivaldi antenna at a distance of 50 cm. The storage capacitor has a charge of over 1.25 V, which is enough to run a temperature sensor placed as the load to be supplied. This demonstrates the validity of the RF energy harvesting system for low-power practical applications. |
Martinez-de-Rioja, Eduardo; Encinar, Jose A; Florencio, Rafael; Tienda, Carolina 3-D Bifocal Design Method for Dual-Reflectarray Configurations With Application to Multibeam Satellite Antennas in Ka-Band Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (1), pp. 450-460, 2019, ISSN: 0018-926X. @article{MartinezdeRioja2019f, title = {3-D Bifocal Design Method for Dual-Reflectarray Configurations With Application to Multibeam Satellite Antennas in Ka-Band}, author = {Eduardo Martinez-de-Rioja and Jose A Encinar and Rafael Florencio and Carolina Tienda}, doi = {10.1109/TAP.2018.2877298}, issn = {0018-926X}, year = {2019}, date = {2019-01-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {67}, number = {1}, pages = {450-460}, abstract = {This paper describes a 3-D bifocal design technique for offset dual-reflectarray antennas (DRAAs) with application to multibeam satellite antennas in Ka-band. The bifocal technique has been used to obtain beams closer than those obtained with a single-focus antenna and, at the same time, to improve the performance of the extreme beams. The technique has been applied to design a multibeam DRAA in an offset compact range configuration to provide 1.12 degrees separation between adjacent beams at 19.7 GHz. A small-scale bifocal DRAA demonstrator has been designed, fabricated, and tested. The demonstrator generates 10 beams alternating in dual-linear polarization when the antenna is illuminated by five adjacent feeds, but the technique can be extended to circular polarization. The results are in a good agreement with the design requirements in the frequency band from 19.2 to 20.2 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper describes a 3-D bifocal design technique for offset dual-reflectarray antennas (DRAAs) with application to multibeam satellite antennas in Ka-band. The bifocal technique has been used to obtain beams closer than those obtained with a single-focus antenna and, at the same time, to improve the performance of the extreme beams. The technique has been applied to design a multibeam DRAA in an offset compact range configuration to provide 1.12 degrees separation between adjacent beams at 19.7 GHz. A small-scale bifocal DRAA demonstrator has been designed, fabricated, and tested. The demonstrator generates 10 beams alternating in dual-linear polarization when the antenna is illuminated by five adjacent feeds, but the technique can be extended to circular polarization. The results are in a good agreement with the design requirements in the frequency band from 19.2 to 20.2 GHz. |
Somolinos, Alvaro; Florencio, Rafael; Gonzalez, Ivan; Catedra, Felipe; Encinar, Jose A; Boix, Rafael R Reflectarray Design to Generate Two Beams per Feed on Arbitrary Shaped Surface by VRT Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). @inproceedings{Somolinos2019a, title = {Reflectarray Design to Generate Two Beams per Feed on Arbitrary Shaped Surface by VRT}, author = {Alvaro Somolinos and Rafael Florencio and Ivan Gonzalez and Felipe Catedra and Jose A Encinar and Rafael R Boix}, issn = {2164-3342}, year = {2019}, date = {2019-01-01}, booktitle = {2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {A design technique has been proposed to generate two closely spaced beams in orthogonal circular polarization using the variable rotation technique (VRT) in reflectarrays printed on arbitrary shaped surfaces fed by a single dual circular polarized (CP) horn. The proposed reflectarray cell for VRT is made of a conductive cross printed on a grounded dielectric. A 1.8-meter offset parabolic reflectarray has been designed to generate six beams in circular polarization with three dual-CP feed-horns, with very promising results for multi spot beam satellite antennas in Ka-band.}, note = {13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A design technique has been proposed to generate two closely spaced beams in orthogonal circular polarization using the variable rotation technique (VRT) in reflectarrays printed on arbitrary shaped surfaces fed by a single dual circular polarized (CP) horn. The proposed reflectarray cell for VRT is made of a conductive cross printed on a grounded dielectric. A 1.8-meter offset parabolic reflectarray has been designed to generate six beams in circular polarization with three dual-CP feed-horns, with very promising results for multi spot beam satellite antennas in Ka-band. |
Martinez-de-Rioja, Eduardo; Encinar, Jose A; Pino, Antonio; Gonzalez-Valdes, Borja Design of Bifocal Dual Reflectarray Antennas in Ka-band to Generate a Multi-Spot Coverage from Geostationary Satellites Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). @inproceedings{MartinezdeRioja2019e, title = {Design of Bifocal Dual Reflectarray Antennas in Ka-band to Generate a Multi-Spot Coverage from Geostationary Satellites}, author = {Eduardo Martinez-de-Rioja and Jose A Encinar and Antonio Pino and Borja Gonzalez-Valdes}, issn = {2164-3342}, year = {2019}, date = {2019-01-01}, booktitle = {2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {This contribution studies the use of bifocal dual reflectarray antennas to provide multi-spot coverage from a geostationary satellite operating in Ka-band. A general 3D bifocal technique has been applied to design a multi-beam dual reflectarray antenna in an offset compact-range configuration, considering three different degrees of beam spacing compression (high, low and no compression) with respect to the equivalent monofocal antenna. The results of the design (bifocal phase distributions, radiation patterns, etc.) have been compared for the three cases under study. The use of suitable reflectarray cells will allow to produce independent beams in each polarization (two beams per feed), so that the bifocal antenna will provide adjacent beams in orthogonal polarizations with 0.56 degrees angular spacing.}, note = {13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution studies the use of bifocal dual reflectarray antennas to provide multi-spot coverage from a geostationary satellite operating in Ka-band. A general 3D bifocal technique has been applied to design a multi-beam dual reflectarray antenna in an offset compact-range configuration, considering three different degrees of beam spacing compression (high, low and no compression) with respect to the equivalent monofocal antenna. The results of the design (bifocal phase distributions, radiation patterns, etc.) have been compared for the three cases under study. The use of suitable reflectarray cells will allow to produce independent beams in each polarization (two beams per feed), so that the bifocal antenna will provide adjacent beams in orthogonal polarizations with 0.56 degrees angular spacing. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Encinar, Jose A; Pino, Antonio; Rodriguez-Vaqueiro, Yolanda; Gonzalez-Valdes, Borja; Rubinos, Oscar; Arias, Marcos Single and Dual Reflectarray Configurations for Multibeam Satellite Antennas in Ka-Band Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). @inproceedings{MartinezdeRioja2019d, title = {Single and Dual Reflectarray Configurations for Multibeam Satellite Antennas in Ka-Band}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Jose A Encinar and Antonio Pino and Yolanda Rodriguez-Vaqueiro and Borja Gonzalez-Valdes and Oscar Rubinos and Marcos Arias}, issn = {2164-3342}, year = {2019}, date = {2019-01-01}, booktitle = {2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {This contribution proposes the use of single and dual reflectarray configurations to provide multi-spot coverage in Ka-band from a geostationary satellite, using a smaller number of apertures and feeds than conventional reflector systems. First, a 1.8-m parabolic reflectarray antenna has been designed to produce multiple spot beams through the generation of two beams per feed in orthogonal circular polarization (CP) at Tx and Rx frequencies. Moreover, a dual RA configuration has been designed to produce two spot beams in orthogonal CP from a single feed in dual linear polarization (LP). The simulated results are compared for the two designed antennas, showing the feasibility of both configurations and their potential to be used for multiple beam applications in Ka-band.}, note = {13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution proposes the use of single and dual reflectarray configurations to provide multi-spot coverage in Ka-band from a geostationary satellite, using a smaller number of apertures and feeds than conventional reflector systems. First, a 1.8-m parabolic reflectarray antenna has been designed to produce multiple spot beams through the generation of two beams per feed in orthogonal circular polarization (CP) at Tx and Rx frequencies. Moreover, a dual RA configuration has been designed to produce two spot beams in orthogonal CP from a single feed in dual linear polarization (LP). The simulated results are compared for the two designed antennas, showing the feasibility of both configurations and their potential to be used for multiple beam applications in Ka-band. |
Martinez-de-Rioja, Daniel; Martinez-de-Rioja, Eduardo; Encinar, Jose A Preliminary Simulations of a 1.8-m Reflectarray Antenna in a Geostationary Satellite to Generate Multi-Spot Coverage Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). @inproceedings{MartinezdeRioja2019c, title = {Preliminary Simulations of a 1.8-m Reflectarray Antenna in a Geostationary Satellite to Generate Multi-Spot Coverage}, author = {Daniel Martinez-de-Rioja and Eduardo Martinez-de-Rioja and Jose A Encinar}, issn = {2164-3342}, year = {2019}, date = {2019-01-01}, booktitle = {2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)}, series = {Proceedings of the European Conference on Antennas and Propagation}, abstract = {This contribution presents preliminary results of a 1.8-m reflectarray antenna proposed to generate a complete multi-spot coverage for transmission in broadband satellite communications in Ka-band. The antenna is designed according to a recently validated design method of reflectarrays which allows to produce four adjacent beams per feed by discriminating simultaneously in frequency and polarization. The simulations consider 27 dual-polarized feeds to illuminate the reflectarray, so the 1.8-m reflectarray is expected to generate 108 beams separated 0.56 degree at two frequencies and two polarizations. The concept enables a reduction in the number of antennas and feeds required on board geostationary communication satellites to provide multi-spot coverages in Ka-band.}, note = {13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This contribution presents preliminary results of a 1.8-m reflectarray antenna proposed to generate a complete multi-spot coverage for transmission in broadband satellite communications in Ka-band. The antenna is designed according to a recently validated design method of reflectarrays which allows to produce four adjacent beams per feed by discriminating simultaneously in frequency and polarization. The simulations consider 27 dual-polarized feeds to illuminate the reflectarray, so the 1.8-m reflectarray is expected to generate 108 beams separated 0.56 degree at two frequencies and two polarizations. The concept enables a reduction in the number of antennas and feeds required on board geostationary communication satellites to provide multi-spot coverages in Ka-band. |
Perez-Palomino, Gerardo; Carrasco, Eduardo; Cano-Garcia, M; Hervas, R; Quintana, X; Geday, M A Design and evaluation of liquid crystal-based pixels for millimeter and sub-millimeter electrically addressable spatial wave modulators Artículo de revista 2019. @article{PerezPalomino2019, title = {Design and evaluation of liquid crystal-based pixels for millimeter and sub-millimeter electrically addressable spatial wave modulators}, author = {Gerardo Perez-Palomino and Eduardo Carrasco and M Cano-Garcia and R Hervas and X Quintana and M A Geday}, doi = {10.1109/iceaa.2019.8879268}, year = {2019}, date = {2019-01-01}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2018 |
Encinar, Jose A; Huang, John Reflectarray Antennas Capítulo de libro Volakis, John (Ed.): Antenna Engineering Handbook, Capítulo Ch. 38, McGraw-Hill Education Ltd, 2018, ISBN: 1259644693. @inbook{Encinar2018a, title = {Reflectarray Antennas}, author = {Jose A Encinar and John Huang}, editor = {John Volakis}, url = {https://www.ebook.de/de/product/31184088/john_volakis_antenna_engineering_handbook.html}, isbn = {1259644693}, year = {2018}, date = {2018-12-04}, booktitle = {Antenna Engineering Handbook}, publisher = {McGraw-Hill Education Ltd}, chapter = {Ch. 38}, abstract = {Reflectarray antennas have shown several advantages with respect to reflector and phased-array counterparts. Reflectarrays have demonstrated their capability to produce contoured beams, independent beam forming in each polarization, multifrequency operation, among others. The limited bandwidth has been significantly overcome by different techniques, including the development of multi-resonant broadband cells and compensation of the spatial phase delay. The use of efficient and accurate analysis and design techniques is essential to optimize the reflectarray antenna to fulfil stringent requirements of beam shaping, cross polarization and operation frequencies. Another key advantage of reflectarray technology is the capability to provide a scanning or reconfiguration of the beam by including controllable phasing cells, as shown in a number of demonstrators. The reflectarray technology is becoming mature enough to design and manufacture antennas compliant with stringent requirements of specific applications in communications, radar, imaging, or satellite antennas. Some challenging examples for space applications have been shown here, such as contoured-beam antennas for broadcasting, multifrequency antennas for data transmission, large inflatable antennas, remote sensing, or high-gain antenna in CubeSats. The results presented here show a great potential of reflectarrays for passive and reconfigurable antennas in a large range of frequencies from microwaves to terahertz frequencies.�}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } Reflectarray antennas have shown several advantages with respect to reflector and phased-array counterparts. Reflectarrays have demonstrated their capability to produce contoured beams, independent beam forming in each polarization, multifrequency operation, among others. The limited bandwidth has been significantly overcome by different techniques, including the development of multi-resonant broadband cells and compensation of the spatial phase delay. The use of efficient and accurate analysis and design techniques is essential to optimize the reflectarray antenna to fulfil stringent requirements of beam shaping, cross polarization and operation frequencies. Another key advantage of reflectarray technology is the capability to provide a scanning or reconfiguration of the beam by including controllable phasing cells, as shown in a number of demonstrators. The reflectarray technology is becoming mature enough to design and manufacture antennas compliant with stringent requirements of specific applications in communications, radar, imaging, or satellite antennas. Some challenging examples for space applications have been shown here, such as contoured-beam antennas for broadcasting, multifrequency antennas for data transmission, large inflatable antennas, remote sensing, or high-gain antenna in CubeSats. The results presented here show a great potential of reflectarrays for passive and reconfigurable antennas in a large range of frequencies from microwaves to terahertz frequencies.� |
Gil, Jose M On the Higher Order Approximations for Efficient Computational Electromagnetics of the Surface Integral Equation Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 66 (12, 2), pp. 7180-7187, 2018, ISSN: 0018-926X. @article{Gil2018, title = {On the Higher Order Approximations for Efficient Computational Electromagnetics of the Surface Integral Equation}, author = {Jose M Gil}, doi = {10.1109/TAP.2018.2869260}, issn = {0018-926X}, year = {2018}, date = {2018-12-01}, journal = {IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION}, volume = {66}, number = {12, 2}, pages = {7180-7187}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Montejo-Garai, Jose R; Ruiz-Cruz, Jorge A; Rebollar, Jesus M 5-way radial power combiner at W-band by stacked waveguide micromachining Artículo de revista NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 905 , pp. 91-95, 2018, ISSN: 0168-9002. @article{MontejoGarai2018, title = {5-way radial power combiner at W-band by stacked waveguide micromachining}, author = {Jose R Montejo-Garai and Jorge A Ruiz-Cruz and Jesus M Rebollar}, doi = {10.1016/j.nima.2018.07.031}, issn = {0168-9002}, year = {2018}, date = {2018-10-01}, journal = {NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, volume = {905}, pages = {91-95}, abstract = {This work presents a 5-way radial power combiner using the very low loss TE01 circular waveguide mode with a performance in the state of art for W-band. The accomplished design shows excellent characteristics: the experimental prototype has a return loss better than 20 dB, with a balance for the amplitudes of (+/- 0.4 dB) and (+/- 3.5 degrees) for the phases, in a 12.8% fractional bandwidth (12 GHz centered at 94 GHz). In order to obtain these specifications, required for instance in plasma diagnosis systems or in power amplifiers, a meticulous step-by-step procedure is developed for both, the design and the challenging manufacture at W-band by stacked waveguide micromachining. The first step involves the design of a mode transducer, from the TE10 mode in the rectangular waveguide to the low-loss TE01 mode in the circular waveguide, with very high purity. In the second step, a 5-way radial power divider is designed. These designs, in order to be successful, have incorporated all the constrains for the manufacturing at W-band, using an E-plane stacked waveguide arrangement for low losses. The power combiner, made up by the transducer and the divider, has been manufactured with great accuracy using a very challenging assembly process, providing experimental results in very good agreement with the theoretical results.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work presents a 5-way radial power combiner using the very low loss TE01 circular waveguide mode with a performance in the state of art for W-band. The accomplished design shows excellent characteristics: the experimental prototype has a return loss better than 20 dB, with a balance for the amplitudes of (+/- 0.4 dB) and (+/- 3.5 degrees) for the phases, in a 12.8% fractional bandwidth (12 GHz centered at 94 GHz). In order to obtain these specifications, required for instance in plasma diagnosis systems or in power amplifiers, a meticulous step-by-step procedure is developed for both, the design and the challenging manufacture at W-band by stacked waveguide micromachining. The first step involves the design of a mode transducer, from the TE10 mode in the rectangular waveguide to the low-loss TE01 mode in the circular waveguide, with very high purity. In the second step, a 5-way radial power divider is designed. These designs, in order to be successful, have incorporated all the constrains for the manufacturing at W-band, using an E-plane stacked waveguide arrangement for low losses. The power combiner, made up by the transducer and the divider, has been manufactured with great accuracy using a very challenging assembly process, providing experimental results in very good agreement with the theoretical results. |
2021 |
Demonstration of a Reflectarray With Near-Field Amplitude and Phase Constraints as Compact Antenna Test Range Probe for 5G New Radio Devices Artículo de revista IEEE Transactions on Antennas and Propagation, 69 (5), pp. 2715-2726, 2021, ISSN: 1558-2221. |
Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band Artículo de revista IEEE Transactions on Antennas and Propagation, 69 (5), pp. 2673-2685, 2021, ISSN: 1558-2221. |
Parabolic Reflectarray Antenna to Generate Multiple Beams in Dual-Frequency and Dual-Circular Polarization Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2021. |
Reconfigurable FSS Based on PIN Diodes for Shared-Aperture X/Ka-Band Antennas Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2021. |
Passive Dual-Polarized Shaped-Beam Reflectarrays to Improve Coverage in Millimeter-Wave 5G Networks Artículo en actas 2021 15th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2021. |
2020 |
Design of Ku- and Ka-Band Flat Dual Circular Polarized Reflectarrays by Combining Variable Rotation Technique and Element Size Variation Artículo de revista Electronics, 9 (6), pp. 985, 2020. |
Bifocal Dual-Reflectarray Antenna to Generate a Complete Multiple Spot Beam Coverage for Satellite Communications in Ka-Band Artículo de revista Electronics, 9 (6), pp. 961, 2020. |
Efficient higher-order discretization of the magnetic field integral equation by means of vector spaces with a solenoidal-no solenoidal decomposition Artículo de revista MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 62 (6), pp. 2168-2173, 2020, ISSN: 0895-2477. |
A 20/30 GHz Reflectarray Backed by FSS for Shared Aperture Ku/Ka-Band Satellite Communication Antennas Artículo de revista IEEE Antennas and Wireless Propagation Letters, 19 (4), pp. 566-570, 2020, ISSN: 1548-5757. |
Bandwidth Improvement of Reflectarray Cells Using Variable Rotation Technique at Two Frequencies for Dual Circular Polarization Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2020. |
Design of a Wideband Linear-to-Circular Polarizing Reflector for Ka-band Satellite Applications Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-4, 2020. |
Preliminary Simulations of a 1.8-m Parabolic Reflectarray in a Geostationary Satellite to Generate a Complete Multi-Spot Coverage for Tx Artículo en actas 2020 14th European Conference on Antennas and Propagation (EuCAP), pp. 1-5, 2020. |
Advanced Reflectarray Antennas for Multispot Coverages in Ka Band Artículo en actas 2020 International Workshop on Antenna Technology (iWAT), pp. 1-4, 2020. |
Design of Broadband Doubly Asymmetrical Branch-Line Directional Couplers Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 68 (4), pp. 1439-1451, 2020, ISSN: 1557-9670. |
Broadband Determination of the Even- and Odd-Mode Propagation Constants of Coupled Lines Based on Two-Port Measurements Artículo de revista IEEE Transactions on Microwave Theory and Techniques, 68 (2), pp. 648-654, 2020, ISSN: 0018-9480. |
Dual-Band Reflectarray to Generate Two Spaced Beams in Orthogonal Circular Polarization by Variable Rotation Technique Artículo de revista IEEE Transactions on Antennas and Propagation, pp. 1-1, 2020, ISSN: 1558-2221. |
Broadband Linear-to-Circular Polarizing Reflector for Space Applications in Ka-Band Artículo de revista IEEE Transactions on Antennas and Propagation, pp. 1-1, 2020, ISSN: 1558-2221. |
Bi-Mode Foster’s Equivalent Circuit of Arbitrary Planar Periodic Structures and its Application to Design Polarization Controller Devices Artículo de revista 2020. |
Analysis and Design of Reflectarray Antennas Based on Delay Lines: A Filter Perspective Artículo de revista IEEE ACCESS, 8 , pp. 44947-44956, 2020, ISSN: 2169-3536. |
2019 |
Development of a high-performance W-band duplexer for plasma diagnosis using a single band with dual circular polarization Artículo de revista NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 947 , 2019, ISSN: 0168-9002. |
Advanced Multibeam Antenna Configurations Based on Reflectarrays: Providing multispot coverage with a smaller number of apertures for satellite communications in the K and Ka bands Artículo de revista IEEE ANTENNAS AND PROPAGATION MAGAZINE, 61 (5), pp. 77-86, 2019, ISSN: 1045-9243. |
Additive Manufacturing of a High-Performance Q-Band Circular TE01 Mode Flared-Type Transducer Artículo de revista IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, 29 (9), pp. 577-579, 2019, ISSN: 1531-1309. |
Analytical expressions of the Q-factor for the complete resonant mode spectrum of the equilateral triangular waveguide cavity Artículo de revista ELECTRONICS LETTERS, 55 (17), pp. 944-946, 2019, ISSN: 0013-5194. |
Dual-Frequency Reflectarray Cell to Provide Opposite Phase Shift in Dual Circular Polarization With Application in Multibeam Satellite Antennas Artículo de revista IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, 18 (8), pp. 1591-1595, 2019, ISSN: 1536-1225. |
Experimental Validation of Generating Two Spaced Beams With Reflectarrays by VRT Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (6), pp. 4263-4268, 2019, ISSN: 0018-926X. |
Flat Reflectarray That Generates Adjacent Beams by Discriminating in Dual Circular Polarization Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (6), pp. 3733-3742, 2019, ISSN: 0018-926X. |
EXPOSURE ASSESSMENT OF PORTABLE WIRELESS DEVICES ABOVE 6 GHZ Artículo de revista RADIATION PROTECTION DOSIMETRY, 183 (4), pp. 489-496, 2019, ISSN: 0144-8420. |
On the Theoretical Maximum Directivity of a Radiating Aperture From Modal Field Expansions Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (4, 2), pp. 2781-2786, 2019, ISSN: 0018-926X. |
Total Field Reconstruction in the Near Field Using Pseudo-Vector E-Field Measurements Artículo de revista IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, 61 (2), pp. 476-486, 2019, ISSN: 0018-9375. |
Efficient Spectral Domain MoM for the Design of Circularly Polarized Reflectarray Antennas Made of Split Rings Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (3), pp. 1760-1771, 2019, ISSN: 0018-926X. |
Reflectarray to Generate Four Adjacent Beams per Feed for Multispot Satellite Antennas Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (2), pp. 1265-1269, 2019, ISSN: 0018-926X. |
Problemas de Introducción al Análisis de Circuitos (plan 2010) Libro Fundetel, ETSIT-UPM, 2019, ISBN: 978-84-7402-427-2. |
Design of a Ku-Band High-Purity Transducer for the TM01 Circular Waveguide Mode by Means of T-Type Junctions Artículo de revista IEEE ACCESS, 7 , pp. 450-456, 2019, ISSN: 2169-3536. |
Higher-Order Mode Electromagnetic Analysis of a Material Sample between Two Flanged Coaxial Probes for Broadband Modelling of Dielectric Measurement Setups Artículo de revista ADVANCES IN MATHEMATICAL PHYSICS, 2019 , 2019, ISSN: 1687-9120. |
A 10-Way Power Divider Based on a Transducer and a Radial Junction Operating in the Circular TM01 Mode Artículo de revista IEEE ACCESS, 7 , pp. 127353-127361, 2019, ISSN: 2169-3536. |
Fast Anaysis of Arrays of Antennas Fed by Substrate Integrated Waveguides Artículo en actas Cracovia, Poland, 2019. |
Applications of the direct domain decomposition based on cylindrical ports in the hybrid Finite Element/Modal Analysis method Artículo en actas pp. 0124–0128, IEEE, Granada, Spain, 2019, ISBN: 978-1-7281-0564-2. |
Decoupled Basis Function Subspaces for Dealing Low-frequency Discretization in the Combined Field Integral Equation Artículo en actas Potes, Cantabria, Spain, 2019. |
A Design Method for waveguide circuits including arbitrary posts using radial waveguide modes scattering Artículo en actas Potes, Cantabria, Spain, 2019. |
Parasitics Impact on the Performance of Rectifier Circuits in Sensing RF Energy Harvesting Artículo de revista Sensors, 19 (22), pp. 4939, 2019, ISSN: 1424-8220. |
RF Energy Harvesting System Based on an Archimedean Spiral Antenna for Low-Power Sensor Applications Artículo de revista Sensors, 19 (6), pp. 1318, 2019, ISSN: 1424-8220. |
3-D Bifocal Design Method for Dual-Reflectarray Configurations With Application to Multibeam Satellite Antennas in Ka-Band Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 67 (1), pp. 450-460, 2019, ISSN: 0018-926X. |
Reflectarray Design to Generate Two Beams per Feed on Arbitrary Shaped Surface by VRT Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). |
Design of Bifocal Dual Reflectarray Antennas in Ka-band to Generate a Multi-Spot Coverage from Geostationary Satellites Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). |
Single and Dual Reflectarray Configurations for Multibeam Satellite Antennas in Ka-Band Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). |
Preliminary Simulations of a 1.8-m Reflectarray Antenna in a Geostationary Satellite to Generate Multi-Spot Coverage Artículo en actas 2019 13TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2019, ISSN: 2164-3342, (13th European Conference on Antennas and Propagation (EuCAP), Krakow, POLAND, MAR 31-APR 05, 2019). |
Design and evaluation of liquid crystal-based pixels for millimeter and sub-millimeter electrically addressable spatial wave modulators Artículo de revista 2019. |
2018 |
Reflectarray Antennas Capítulo de libro Volakis, John (Ed.): Antenna Engineering Handbook, Capítulo Ch. 38, McGraw-Hill Education Ltd, 2018, ISBN: 1259644693. |
On the Higher Order Approximations for Efficient Computational Electromagnetics of the Surface Integral Equation Artículo de revista IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 66 (12, 2), pp. 7180-7187, 2018, ISSN: 0018-926X. |
5-way radial power combiner at W-band by stacked waveguide micromachining Artículo de revista NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 905 , pp. 91-95, 2018, ISSN: 0168-9002. |
