Multi-antenna system based on substrate integrated waveguide for Ka-band traffic-monitoring radar applications

In this paper, a multi-antenna system designed with one antenna for transmitter and the other three for receiver is proposed and demonstrated for Ka-band traffic-monitoring radar applications with simultaneous functionality of range, velocity and angle detection. Each antenna consists of 4 × 20 substrate integrated waveguide (SIW) slot array for wide azimuth field of view and low ground reflection. The scan angle of +5/-5 degree in azimuth plane (E-plane) for two receiver antennas, respectively, is simply realized by rotating the compact feeding network with a specific angle. The design details are given and the isolation between antennas with different orientations is also investigated. The prototyped antenna has a measured gain of about 22 dBi and side lobe suppression of 20 dB in the H-plane, while the bandwidth for the 10-dB return loss is 1.25 GHz.