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Papers by Daniel Martinez-De-Rioja

Research paper thumbnail of Bifocal Dual Reflectarray with Curved Main Surface

Electronics

This paper presents a novel approach to synthesizing curved reflectarrays using Geometrical Optic... more This paper presents a novel approach to synthesizing curved reflectarrays using Geometrical Optics (GO). It introduces the concepts of virtual normal and path length shift, which enable a vector-based formulation of the problem that can be solved using ray tracing techniques. The formulation is applied for the design of two different versions of a Dual Bifocal Reflectarray with a parabolic main surface and a flat subreflectarray. The first version aims to enhance the performance of the multibeam antenna by providing a focal ring located at the feed cluster plane. The second version focuses on improving the scanning characteristics of the antenna in the horizontal plane by incorporating two foci. The synthesis procedure yields samples of the path length shift or its derivatives. To reconstruct the phase distribution, an interpolation scheme is employed and described in this paper. Numerical results are presented for both the focal-ring and two-foci configurations, demonstrating the f...

Research paper thumbnail of Dual Circularly Polarized Reflectarray Antenna for High Throughput Links from Small Satellites

2023 17th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Evaluation of a Dual-Circularly-Polarized Reflective Metasurface as a Plane Wave Generator in Ka-Band

2023 17th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Gain Equalized Reflectarray Antenna for High Throughput Satellites

2023 IEEE Radio and Antenna Days of the Indian Ocean (RADIO)

Research paper thumbnail of Frequency Selective Beam Shaping Technique to Provide Equal Beam Coverage Using Reflectarray Antennas for Dual-Band Multi-Spot Satellites

IEEE Transactions on Antennas and Propagation

Research paper thumbnail of Near-Field Model for the Computation of Coverage Generated by an IRS: Formulation and Validation

2022 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO)

Research paper thumbnail of Multibeam Reflectarrays in Ka-Band for Efficient Antenna Farms Onboard Broadband Communication Satellites

Sensors, 2021

Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a ... more Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a multispot coverage. In this paper, four different multibeam antenna farms are proposed to generate the complete multispot coverage using only two multibeam reflectarrays, making it possible to halve the number of required antennas onboard the satellite. The proposed solutions include flat and curved reflectarrays with single or dual band operation, the operating principles of which have been experimentally validated. The designed multibeam reflectarrays for each antenna farm have been analyzed to evaluate their agreement with the antenna requirements for real satellite scenarios in Ka-band. The results show that the proposed configurations have the potential to reduce the number of antennas and feed-chains onboard the satellite, from four reflectors to two reflectarrays, enabling a significant reduction in cost, mass, and volume of the payload, which provides a considerable benefit for satellite operators.

Research paper thumbnail of Preliminary simulations of flat and parabolic reflectarray antennas to generate a multi‐spot coverage from a geostationary satellite

IET Microwaves, Antennas & Propagation

Research paper thumbnail of Dual-frequency Reflectarray Cells to Generate Closely Spaced Beams in Orthogonal Circular Polarization

2019 International Conference on Electromagnetics in Advanced Applications (ICEAA)

A dual-frequency reflectarray cell is proposed in this work to provide a progressive phase shift ... more A dual-frequency reflectarray cell is proposed in this work to provide a progressive phase shift of opposite sign in each circular polarization (CP), by applying a variable rotation technique (VRT) [1], The proposed reflectarray cell consists of two symmetrical arcs printed on the top surface and two orthogonal sets of parallel dipoles printed on two levels of a grounded dielectric substrate, see Figure 1. The arcs and dipoles are rotated independently to control the phase in CP at the lower (19.7 GHz) and higher (29.5 GHz) frequencies respectively. This reflectarray cell can be used to generate two adjacent beams in orthogonal CP per feed at transmission (Tx) and reception (Rx), in order to reduce the number of feeds and antennas required in current multi-spot satellites operating in Ka-band, as proposed in [1] for a single frequency band.

Research paper thumbnail of A Simple Beamforming Technique for Intelligent Reflecting Surfaces in 5G Scenarios

2022 International Workshop on Antenna Technology (iWAT)

Research paper thumbnail of Advanced Reflectarray Antennas for Multispot Coverages in Ka Band

2020 International Workshop on Antenna Technology (iWAT)

This contribution proposes three different multibeam antenna farms based on reflectarrays to be u... more 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.

Research paper thumbnail of Dual-Band Polarizer Reflectarray Operating in Dual-CP for High-Gain Antenna in CubeSats

2022 16th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Preliminary Results of a Multibeam Reflectarray Antenna in Ka-band for LEO Satellites Constellations

2022 16th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of A Multibeam Parabolic Reflectarray for Onboard Tx and Rx Satellite Antennas At the Ka Band

2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018

The design and performance of a multi-fed reflectarray antenna built on a parabolic surface is ad... more The design and performance of a multi-fed reflectarray antenna built on a parabolic surface is addressed in this communication. The proposed design can be used as onboard satellite Tx and Rx antenna in Ka-band and it is able to reduce to half the required number of antennas due to the ability of the reflectarray to produce two beams per horn by polarization discrimination. An application example providing up to 108 beams by only two antennas is described.

Research paper thumbnail of Multibeam Reflectarrays in Ka-Band for Efficient Antenna Farms Onboard Broadband Communication Satellites

Sensors, 2020

Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a ... more Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a multispot coverage. In this paper, four different multibeam antenna farms are proposed to generate the complete multispot coverage using only two multibeam reflectarrays, making it possible to halve the number of required antennas onboard the satellite. The proposed solutions include flat and curved reflectarrays with single or dual band operation, the operating principles of which have been experimentally validated. The designed multibeam reflectarrays for each antenna farm have been analyzed to evaluate their agreement with the antenna requirements for real satellite scenarios in Ka-band. The results show that the proposed configurations have the potential to reduce the number of antennas and feed-chains onboard the satellite, from four reflectors to two reflectarrays, enabling a significant reduction in cost, mass, and volume of the payload, which provides a considerable benefit for s...

Research paper thumbnail of Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band

IEEE Transactions on Antennas and Propagation, 2021

This contribution describes the design of a multibeam parabolic reflectarray to produce two adjac... more This contribution describes the design of a multibeam parabolic 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 Variable Rotation Technique (VRT) has been applied to 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 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 Ka-band, enabling to halve the number of onboard antennas and feeds.

Research paper thumbnail of Preliminary Simulations of a 1.8-m Parabolic Reflectarray in a Geostationary Satellite to Generate a Complete Multi-Spot Coverage for Tx

2020 14th European Conference on Antennas and Propagation (EuCAP), 2020

A parabolic reflectarray antenna has been proposed to generate a complete cellular coverage in tr... more 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.

Research paper thumbnail of Bandwidth Improvement of Reflectarray Cells Using Variable Rotation Technique at Two Frequencies for Dual Circular Polarization

2020 14th European Conference on Antennas and Propagation (EuCAP), 2020

The bandwidth behavior has been studied and improved for a reflectarray cell formed by two symmet... more 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.

Research paper thumbnail of High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat

Electronics, 2021

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to genera... more This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight...

Research paper thumbnail of Single and Dual Reflectarray Configurations for Multibeam Satellite Antennas in Ka-Band

2019 13th European Conference on Antennas and Propagation (EuCAP), 2019

This contribution proposes the use of single and dual reflectarray configurations to provide mult... more 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.

Research paper thumbnail of Bifocal Dual Reflectarray with Curved Main Surface

Electronics

This paper presents a novel approach to synthesizing curved reflectarrays using Geometrical Optic... more This paper presents a novel approach to synthesizing curved reflectarrays using Geometrical Optics (GO). It introduces the concepts of virtual normal and path length shift, which enable a vector-based formulation of the problem that can be solved using ray tracing techniques. The formulation is applied for the design of two different versions of a Dual Bifocal Reflectarray with a parabolic main surface and a flat subreflectarray. The first version aims to enhance the performance of the multibeam antenna by providing a focal ring located at the feed cluster plane. The second version focuses on improving the scanning characteristics of the antenna in the horizontal plane by incorporating two foci. The synthesis procedure yields samples of the path length shift or its derivatives. To reconstruct the phase distribution, an interpolation scheme is employed and described in this paper. Numerical results are presented for both the focal-ring and two-foci configurations, demonstrating the f...

Research paper thumbnail of Dual Circularly Polarized Reflectarray Antenna for High Throughput Links from Small Satellites

2023 17th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Evaluation of a Dual-Circularly-Polarized Reflective Metasurface as a Plane Wave Generator in Ka-Band

2023 17th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Gain Equalized Reflectarray Antenna for High Throughput Satellites

2023 IEEE Radio and Antenna Days of the Indian Ocean (RADIO)

Research paper thumbnail of Frequency Selective Beam Shaping Technique to Provide Equal Beam Coverage Using Reflectarray Antennas for Dual-Band Multi-Spot Satellites

IEEE Transactions on Antennas and Propagation

Research paper thumbnail of Near-Field Model for the Computation of Coverage Generated by an IRS: Formulation and Validation

2022 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO)

Research paper thumbnail of Multibeam Reflectarrays in Ka-Band for Efficient Antenna Farms Onboard Broadband Communication Satellites

Sensors, 2021

Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a ... more Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a multispot coverage. In this paper, four different multibeam antenna farms are proposed to generate the complete multispot coverage using only two multibeam reflectarrays, making it possible to halve the number of required antennas onboard the satellite. The proposed solutions include flat and curved reflectarrays with single or dual band operation, the operating principles of which have been experimentally validated. The designed multibeam reflectarrays for each antenna farm have been analyzed to evaluate their agreement with the antenna requirements for real satellite scenarios in Ka-band. The results show that the proposed configurations have the potential to reduce the number of antennas and feed-chains onboard the satellite, from four reflectors to two reflectarrays, enabling a significant reduction in cost, mass, and volume of the payload, which provides a considerable benefit for satellite operators.

Research paper thumbnail of Preliminary simulations of flat and parabolic reflectarray antennas to generate a multi‐spot coverage from a geostationary satellite

IET Microwaves, Antennas & Propagation

Research paper thumbnail of Dual-frequency Reflectarray Cells to Generate Closely Spaced Beams in Orthogonal Circular Polarization

2019 International Conference on Electromagnetics in Advanced Applications (ICEAA)

A dual-frequency reflectarray cell is proposed in this work to provide a progressive phase shift ... more A dual-frequency reflectarray cell is proposed in this work to provide a progressive phase shift of opposite sign in each circular polarization (CP), by applying a variable rotation technique (VRT) [1], The proposed reflectarray cell consists of two symmetrical arcs printed on the top surface and two orthogonal sets of parallel dipoles printed on two levels of a grounded dielectric substrate, see Figure 1. The arcs and dipoles are rotated independently to control the phase in CP at the lower (19.7 GHz) and higher (29.5 GHz) frequencies respectively. This reflectarray cell can be used to generate two adjacent beams in orthogonal CP per feed at transmission (Tx) and reception (Rx), in order to reduce the number of feeds and antennas required in current multi-spot satellites operating in Ka-band, as proposed in [1] for a single frequency band.

Research paper thumbnail of A Simple Beamforming Technique for Intelligent Reflecting Surfaces in 5G Scenarios

2022 International Workshop on Antenna Technology (iWAT)

Research paper thumbnail of Advanced Reflectarray Antennas for Multispot Coverages in Ka Band

2020 International Workshop on Antenna Technology (iWAT)

This contribution proposes three different multibeam antenna farms based on reflectarrays to be u... more 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.

Research paper thumbnail of Dual-Band Polarizer Reflectarray Operating in Dual-CP for High-Gain Antenna in CubeSats

2022 16th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of Preliminary Results of a Multibeam Reflectarray Antenna in Ka-band for LEO Satellites Constellations

2022 16th European Conference on Antennas and Propagation (EuCAP)

Research paper thumbnail of A Multibeam Parabolic Reflectarray for Onboard Tx and Rx Satellite Antennas At the Ka Band

2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018

The design and performance of a multi-fed reflectarray antenna built on a parabolic surface is ad... more The design and performance of a multi-fed reflectarray antenna built on a parabolic surface is addressed in this communication. The proposed design can be used as onboard satellite Tx and Rx antenna in Ka-band and it is able to reduce to half the required number of antennas due to the ability of the reflectarray to produce two beams per horn by polarization discrimination. An application example providing up to 108 beams by only two antennas is described.

Research paper thumbnail of Multibeam Reflectarrays in Ka-Band for Efficient Antenna Farms Onboard Broadband Communication Satellites

Sensors, 2020

Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a ... more Broadband communication satellites in Ka-band commonly use four reflector antennas to generate a multispot coverage. In this paper, four different multibeam antenna farms are proposed to generate the complete multispot coverage using only two multibeam reflectarrays, making it possible to halve the number of required antennas onboard the satellite. The proposed solutions include flat and curved reflectarrays with single or dual band operation, the operating principles of which have been experimentally validated. The designed multibeam reflectarrays for each antenna farm have been analyzed to evaluate their agreement with the antenna requirements for real satellite scenarios in Ka-band. The results show that the proposed configurations have the potential to reduce the number of antennas and feed-chains onboard the satellite, from four reflectors to two reflectarrays, enabling a significant reduction in cost, mass, and volume of the payload, which provides a considerable benefit for s...

Research paper thumbnail of Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band

IEEE Transactions on Antennas and Propagation, 2021

This contribution describes the design of a multibeam parabolic reflectarray to produce two adjac... more This contribution describes the design of a multibeam parabolic 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 Variable Rotation Technique (VRT) has been applied to 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 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 Ka-band, enabling to halve the number of onboard antennas and feeds.

Research paper thumbnail of Preliminary Simulations of a 1.8-m Parabolic Reflectarray in a Geostationary Satellite to Generate a Complete Multi-Spot Coverage for Tx

2020 14th European Conference on Antennas and Propagation (EuCAP), 2020

A parabolic reflectarray antenna has been proposed to generate a complete cellular coverage in tr... more 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.

Research paper thumbnail of Bandwidth Improvement of Reflectarray Cells Using Variable Rotation Technique at Two Frequencies for Dual Circular Polarization

2020 14th European Conference on Antennas and Propagation (EuCAP), 2020

The bandwidth behavior has been studied and improved for a reflectarray cell formed by two symmet... more 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.

Research paper thumbnail of High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat

Electronics, 2021

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to genera... more This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight...

Research paper thumbnail of Single and Dual Reflectarray Configurations for Multibeam Satellite Antennas in Ka-Band

2019 13th European Conference on Antennas and Propagation (EuCAP), 2019

This contribution proposes the use of single and dual reflectarray configurations to provide mult... more 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.