Wideband Compact Comb-Line Antenna Array for 79 GHz Automotive Radar Applications

A wideband microstrip comb-line antenna array is developed for 79 GHz multiple-input-multiple-output radar applications. This array is composed of four radiating subarrays, with 180° phase shift. This topology leads to a more stable radiation pattern behavior and broadside gain flatness along the frequency bandwidth. The antenna is taped out with a new high-resolution multilayer printed circuit board (PCB) technology, called “any-layer PCB.” This technology provides the possibility to stack small microvias, instead of using thick machine-drilled vias. A measured impedance and gain bandwidth of 12.5% is achieved. The sidelobe suppression is higher than 15 dB, and the array gain is 12.36 dBi at 79 GHz.