Design of a W-band dual-polarization monopulse reflector antenna

This paper introduces a W-band dual-polarization reflector antenna which combines one dual-polarized transmit-receive SUM channel and two single-polarized DIFF receiving channels. The feed of the antenna consists of four OMTs (Orth Mode Transducer) to realize dual-polarization monopulse angle measurement. Four horns of the feed are combined into one radiation aperture by a coupled retracted structure to decrease side-lobes. The SUM beam gain of the proposed antenna is over 41 dBi and the aperture efficiency of 60% is achieved, cross-polarization level is better than –43 dB. The first sidelobe level is better than -30dB. The null-depth is better than -20dB.