Dual-Polarized Shared-Cavity Waveguide Slot Antenna for 77 GHz Automotive Radar Applications

A dual-polarized shared-cavity waveguide slot antenna is proposed for millimeter(mm)-wave automotive radar applications. The antenna is composed of three layers, which are a slot layer, a cavity layer and a feeding layer. An array of cross-shape slots is cut on the top of the slot layer. A groove and two slits are introduced above the slots array. The cavity layer is a ridge waveguide cavity, which is coupled with the feeding layer. The ridge waveguide cavity can be excited by two Ports through a quasi-square cavity to generate mode TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">140</inf>for vertical polarization and TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">011</inf>for horizontal polarization. The simulated results show that the proposed antenna has a bandwidth of 76-77.9 GHz. The gains are around 15 dBi and the side lobe level is lower than −17.5 dB.