A Gap Waveguide-Based 2x2 Circularly-polarized Monopulse Antenna Array

Paper submitted to The European Conference on Antennas and Propagation 2022 (EuCAP), 27 March - 1 April 2022, Madrid (Spain).This paper presents a circular-polarized gap-waveguide-based compact monopulse array antenna for millimeter-wave tracking applications at Ka-band (29 to 31 GHz). The gap waveguide planar monopulse comparator network is integrated in a single layer with a 2x2 corporate-fed network combining ridge gap and groove gap waveguides. Radiating cavities consist of cubes with chamfered corners. Preliminary results show a bandwidth of 2 GHz with input reflection coefficients better than -20 dB for both ports of the antenna. In addition, the isolation between ports is greater than 50 dB. The design allows for scalability to build higher gain arrays from the antenna presented in this communication.This work is part of the projects PID2019-107688RB-C22 and PID2019-103982RB-C43 funded by the Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033