A Ka-band Compact Single-Layer Gap Waveguide Monopulse Slot Array Antenna

This paper presents a gap-waveguide-based compact monopulse array antenna for millimeter-wave tracking applications at Ka-band (27.5 to 30.5 GHz). A low-loss Magic-Tee is designed to be used in a monopulse comparator network. The gap waveguide planar monopulse comparator network is integrated in a single layer with a 2 × 2 corporate-fed network combining ridge gap and groove gap waveguides. Simulated results show bandwidths of 10% with input reflection coefficients better than −12 dB for the sum and difference ports over the frequency band of interest. Besides, the isolation between sum and difference ports is more than 50 dB. The simplicity of the design and the fact that it is housed in a single layer permit easy scaling to larger arrays.