Pillbox Reflector based Low-Profile Millimeter-Wave Shared Aperture Dual-Polarized Multi-Beam Antenna

A millimeter-wave multi-beam antenna is presented with dual-polarized radiation characteristics. The proposed antenna is composed of a shared aperture dual-polarized slotted waveguide antenna (SWA) array and two pillbox beamforming networks (BFNs). The dual-polarized radiation characteristic of the SWA array is achieved by the cross-placed vertically polarized (VP) and horizontally polarized (HP) SWAs. The input ports of the VP and HP SWAs are located at the two ends of the dual-polarized array, connected with two pillbox BFNs. The sources (H-plane horns) at the different positions of the pillbox BFNs can excite different phase gradients to the SWA array, thus achieving the multi-beams switching. In addition, the aperture sizes of the H-plane horns are optimized to suppress the dropped gain of the steered beams. In our simulation, the proposed antenna can achieve 7 beams with the maximum beam steering range of ±28° for both HP and VP beams, and the maximum gain difference of the steered beams is 1.6 dB.