Multilayer Compact Grid Antenna Array for 79 GHz Automotive Radar Applications

A novel wideband compact grid antenna array is developed for 79 GHz multiple-input multiple-output radar applications. The key issue is the stable radiation pattern with flat-gain characteristic along the whole frequency bandwidth, which is very advantageous for the targeted radar applications. The antenna is taped out with the new high-resolution multilayer printed circuit board (PCB) technology called “Any-Layer PCB.” This technology provides the possibility to stack microvias in PCBs and reduce the fabrication cost compared with other multilayer technologies in millimeter-wave bands. With this feature, the width of the array has been compacted with 17.2%, which leads to a higher sidelobe suppression and an enhancement of the field of view in radar applications. A combined impedance and 3 dB gain bandwidth of 9.6% is achieved. The gain and sidelobe level are 13.52 and -14 dB at 79 GHz, respectively.