Millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip antenna

A millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip patch antenna has been proposed in this paper. The stepped rectangular waveguide provides smooth impedance matching from standard rectangular waveguide to oversized rectangular waveguide. In order to obtain good amplitude balance, four symmetrical microstrip patch antennas are utilized. A Ka-band four-way passive power combiner is designed and measured. The measured results show a reasonable agreement with the simulated ones.