A compact millimeter-wave horn antenna array fabricated through layer-by-layer stereolithography

In this paper, a millimeter-wave dielectrically filled compact horn antenna array is presented, which is fabricated through layer-by-layer stereolithography. The antennas are well suited for phased array circuits due to their ability to interface with microstrip circuitry through low profile microstrip to waveguide transitions. The aperture size of the horn antenna is 0.5 lambda square, and the entire antenna and waveguide feeding structure does not exceed this area, thereby allowing for compact integration of multiple antenna elements. The antenna demonstrates broad bandwidth with better than -10 dB return loss from 35 to 39.5 GHz. The radiation patterns of a single horn antenna show broad angular beamwidth for wide-angle phased array scanning, and there is 5.7 dB gain with better than 20 dB cross-polarization discrimination at broadside.