Low-cost multi-layer antenna sub-array for 79 GHz short-range radar applications

A new wideband cavity-backed aperture coupled microstrip antenna is presented for 79 GHz short-range multi-input multi-output radar applications. This design is based on a sub-array consisting of two single elements, and each element is founded on a cavity backed aperture coupled patch antenna. A microstrip to strip-line transition and a series feeding topology is used to feed the elements. The antennas are manufactured by using a new high-resolution multi-layer PCB technology. This technology is able to deliver high-resolution stacked micro-vias on very thin substrates. The performance of the designed antenna has been verified by both simulations and measurements. The bandwidth is 11.2%, and the maximum gain and efficiency are 6.05 dBi and 80% along 77–81 GHz.