A Report on New Antennas for Satellite Communications on-the-move in Ka-band

This project was initiated in 2017 within the framework of the Spanish national research program, funded by the ministry of economics, industry and competitiveness. The scope of this project is focused on the design of ground terminals for the new generation of high-throughput satellites operating in the Ka band (from 19 to 31 GHz

Comments on “Ka-Band Coplanar Magic-T Based on Gap Waveguide Technology”

In the title paper, the author proposes a Ka-Band Coplanar Magic-T Based on Gap-Waveguide (GW) Technology. The major novelty claimed in the paper is the combination of ridge-gap and E-plane groove-gap waveguides for Ka-band applications. However, such combination of these two types of waveguides in GW technology was firstly proposed in 2017. This combination allows for the realization of numerous devices, and distribution networks in the millimeter-wave band. This comment aims to properly frame the evolution of the use of RGW-GGW networks and how their use can be useful for new mm-wave band devices. While the author’s Magic-T introduces a new feature by using a 4-port network, it is clear that the concept relies on previous ideas not mentioned in the manuscript and this can lead to confusion about its actual novel contributions. In addition, we intend to give the microwave community a proper perspective of the above work’s frame of reference

Novel Asymmetric T-Shaped Radiating Element for Circularly-Polarized Waveguide Slot Arrays

Waveguide slot arrays are a widely used solution to attain linearly-polarized high-gain antennas. In this paper, an all-metal T-shaped radiating element is conceived with the aim to replace the usual rectangular slots and attain circularly-polarized arrays, preserving their good properties. The polarization conversion is made possible thanks to the inclusion of a parasitic arm perpendicular to the main active slot. Due to the fact that this second arm is not directly fed by the waveguide but coupled to the active slot, the T-shaped element can be used in any array originally formed by metallic rectangular slots. The design of resonant shunt arrays has been addressed here for validation purposes. The experimental results of two sample linear arrays at 30 GHz demonstrate the design accuracy and manufacturing reliability, reporting an axial ratio below 2 dB within a bandwidth of 1.9 GHz and a peak efficiency around 98%.This work was supported by the Spanish Government, Agencia Estatal de Investigación (AEI), under project PID2019-107688RB-C22

True-Time-Delay Mechanical Phase Shifter in Gap Waveguide Technology for Slotted Waveguide Arrays in Ka-band

This paper proposes a novel all-metal mechanical phase shifter in gap waveguide technology. The phase shifter is aimed at providing beam-scanning capabilities to conventional slot array antennas along the elevation plane. To validate experimentally the beam-steering functionality, a 4×8 slot-array antenna has been designed and fabricated, along with the phase-shifting mechanism. The whole antenna consists of two pieces: a lower rotatable block, which changes the length of concentric Groove Gap Waveguides, and an upper fixed block, where the slot-array antenna is placed. Experimental results validate the proposed concept, having obtained steering angles of up to 25∘, with gain levels around 20 dBi with an antenna efficiency close to 90%. A reflection coefficient below –10 dB is achieved for a wide range of rotation angles from 29.5 GHz to 30.5 GHz. The proposed phase shifter is completely scalable to any array size and its true-time-delay nature enables wide steering ranges for closely-spaced slot arrays with wideband radiation performance.This work was supported by the Spanish Ministry of Economics and competitiveness under project TEC2016-79700-C2-1-R

Dual-Band Single-Layer Slot Array Antenna Fed by K/Ka-Band Dual-Mode Resonators in Gap Waveguide Technology

This paper presents a 4 x 4 single-layer dual-band array antenna operating in K and Ka-band using Gap Waveguide technology (GW). Radiating elements consist of I-shaped slots located on the top plate of the antenna and cavity backed by a novel coaxial cavity with dual-frequency operation. The antenna presents two ports, one for each band, which radiate a directive far field pattern with linear polarization. A single-layer high-bandwidth corporate-feed network is used to excite the cavities. In addition, a diplexer is integrated as part of the network to separate both working bands. Experimental results show impedance and radiation pattern bandwidths larger than 2 GHz in both bands.This work has been supported by the Spanish Ministry of Science and Innovation under the project PID2019-107688RB-C22

Single-Layer Sequential Rotation Network in Gap Waveguide for a Wideband Low-Profile Circularly Polarized Array Antenna

A low-profile circularly-polarized sequential rotation fed 4x4 array antenna working in the Ka-band from 27.5 GHz to 31 GHz is presented. The particularity of the antenna lies in its single-layer sequential rotation feed network implemented in a bed of nails using a combination of groove and ridge gap waveguides. The basic radiating element is one slot loaded by a simple coffee-bean-shaped parasitic element on top. Experimental results show an antenna matching below −10 dB in a 13.6% bandwidth and a measured axial ratio below 1.3 dB in the desired band.This work was supported in part by the Ministry of Science and Innovation of the Spanish Government, in part by the Agencia Estatal de Investigacion (AEI) under Project PID2019-107688RB-C22 and Project AEI/10.13039/501100011033, and in part by the University of Alicante under the Research Project GRE20-06-A

Antena plana con polarización circular para comunicaciones por satélite en banda Ka: desafíos y resultados

Comunicación presentada en URSI'19, XXXIV Simposium Nacional de la Unión Científica Internacional de Radio, Sevilla, 4-6 septiembre 2019.This paper reports the design and measurements of two radiating panels (TX / RX) for satellite communications on the move in Ka-band. A multilayer structure, both in the power distribution network and in the circularly-polarized radiating element, is adopted to ensure the demanded bandwidth. These panels provide answers and solve problems for future antennas with similar characteristics.Las actividades que han llevado a la obtención de estos resultados han sido financiadas parcialmente por la Agencia Espacial Europea bajo el contrato 400010860913NLUS- proyecto LOCOMO y por el Ministerio de Economía y Competitividad bajo el proyecto TEC2013-47360-C3-3-P

Agrupación de ranuras alimentadas por una novedosa guía semi-modo en Gap Waveguide

Comunicación presentada en el XXXVII Simposio Nacional de la URSI, Málaga, 5-7 septiembre 2022.This paper presents a novel antenna feed network that significantly facilitates the design and fabrication in Gap Waveguide technology. In particular, a 1x4 linearly polarized Ka-band antenna array with a novel corporate distribution network using a half-mode groove-gap waveguide (HM-GGW). The good simulated results obtained from 29 GHz to 31 GHz by this breadboard give the first validity to this new development for GW.Este trabajo forma parte de los proyectos PID2019-107688RB-C22 y PID2019-103982RB-C43 financiados por el Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033

Wideband Coffee-Bean Shaped Radiating Element for Circularly-Polarized Waveguide Slot Arrays

Paper submitted to the 15th European Conference on Antennas and Propagation (EuCAP), 22-26 March 2021.A wideband coffee-bean shaped radiating element for circularly-polarized waveguide slot arrays is presented. The proposed solution is based on a very simple polarizer aimed to be integrated into flat panel antennas in the millimeter-wave band. For validation purposes, a slot array fed by a groove gap waveguide network at 30 GHz is taken as a feeder. Simulated results using periodic boundary conditions in a 2×2 unit cell are presented in this work. Preliminary results show a frequency bandwidth of 4 GHz with input reflection coefficient better than −-10 dB. It is worth stressing the good polarization purity achieved, being below 1.5 dB from 29 GHz to 31 GHz and below 3 dB in the whole band of interest (28 to 32 GHz).This work has been supported by the Spanish Ministry of Science, Innovation and Universities (Ministerio de Ciencia, Innovación y Universidades) under project PID2019-107688RB-C22

Selective Laser Sintering Manufacturing as a Low Cost Alternative for Flat-Panel Antennas in Millimeter-Wave Bands

In this paper, the capabilities of Selective Laser Sintering metal 3D-Printing technology to achieve a lightweight and cost-effective flat panel antenna in the millimeter wave band are studied. Specifically, two identical dual-band 4×4 array antennas working in the K and Ka bands have been manufactured; one with Selective Laser Sintering (SLS) and one using computer numerical control (CNC). Measured performance of the SLS antenna prototype is benchmarked with the performance of the previously measured CNC antenna. Experimental results reveal the strengths and weaknesses of this particular low-cost additive manufacturing technique with respect to traditional subtractive manufacturing techniques.This work has been supported by the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía y Competitividad) under the project PID2019-107688RB-C22