High-Efficiency Injection-Molded Waveguide Horn Antenna Array for 76-81 GHz Automotive Radar Applications

A high-efficiency waveguide horn antenna array for 76-81 GHz automotive medium-range MIMO radar is designed, fabricated, and tested. The antenna consists of a linear array with eight elements and is realized by assembling two injection-molded plastic layers metalized using physical vapor deposition (PVD) and electroplating. Excellent free-space performance is achieved in the 76-81 GHz band, with measured impedance bandwidth of 20.8% and a maximal measured realized gain of 17.1 dBi at 78.5 GHz. With a measured efficiency of 91% (-0.4 dB), the built prototype represents an attractive alternative to conventional PCB technology.