Differential Multi-Layer Compact Grid Antenna Array for 79 GHz Automotive Radar Applications

A novel wide band compact grid antenna array is developed for 79 GHz MIMO 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 multi-layer PCB technology, called “Any-Layer PCB”. This technology provides the possibility to stack micro-vias in PCB boards and reduce the fabrication cost compared to other multi-layer technologies in mm-wave bands. With this feature, the width of the array has been compacted with 17.2%, which leads to a higher side lobe suppression and an enhancement of the field of view in radar applications. A combined impedance and 3-dB gain band width of 9.6% is achieved. The gain and SLL are 13.52 dB and -14 dB at 79 GHz, respectively.