A Compact Robust Feed Antenna for Passive Millimeter-Wave Imaging Using Gap Waveguide Technology

In this paper, a low-cost feed array for passive millimeter-wave(PMMW) imaging system based on focal plane array(FPA) is designed. The array has 32 groove gap waveguide(GGWG) horn units, evenly staggered around a focal plane of an ellipsoid reflector. The working frequency band of the horn unit covers W band, the gain varies from 10.4 dBi to 14dBi, the sidelobe level of both E-plane and H-plane is less than −18dB. And the designed horn unit has good beam symmtric that the HPBW difference between E-plane and H-plane is less than 3° in the whole working frequency band. The designed feed array is compact, robust and low-cost. The port isolation is less than −40dB.