A Compact Gap-Waveguide Dual-Polarized Ka-Band Feed for 50dBi Reflector Antennas With Tracking Function

A dual-polarized Ka-band feed based on gap waveguide (GW) technology for an ultra-high-gain reflector antenna is presented. The feed provides SUM-beams for data transfer and DIFF-beams for tracking. The whole reflector antenna is composed of the feed and a dual-reflector Cassegraine antenna. The feed has been prototyped, and the measured reflection coefficients for the horizontally and the vertically polarized SUM-beam ports are below −10 dB and −8 dB over 30.8–38 GHz, respectively. The measured feed radiation patterns agree well with the simulated ones. The dual-reflector Cassegraine antenna has been designed and simulated by using GRASP with the simulated far-field function of the proposed feed, showing that the reflector antenna achieves SUM-beam gains above 50 dBi and the null depth of the DIFF-beams are more than 30 dB below the maximum of SUM-beams.