76 GHz post-wall waveguide fed parallel plate slot arrays for car-radar applications

Parallel plate slot array is an attractive candidate for high-efficiency and mass-producible planar phased array antennas for millimeter-wave applications since the transmission loss is generally small in comparison with other feed lines. We have proposed a novel single-layer feed structure of a post-wall waveguide to excite a plane TEM wave. 76 GHz post-wall waveguide fed parallel plate slot arrays have been designed to suppress the sidelobes and to realize the 45-degree linear polarization for car-radar applications. The sidelobes have been suppressed below -18dB both in the E and H planes. The cross polarization has been suppressed below -26 dB in the boresight in the 45-degree linearly polarized antenna.