A High Isolation Duplex Antenna for 79GHz FMCW Radar System.

A simple, easy to integrate, and high isolation level duplex antenna is presented in this paper. This antenna, consisting of a rat-race coupler and a circular waveguide to GCPW transition, can be realized in a standard printed circuit board (PCB) process. The transition enables low losses when connected to an RF chip for a center frequency of 79 GHz, and is particularly suitable for high-frequency applications. Simulated results show that the good return loss and high isolation between transmitting and receiving ports are achieved from 77GHz to 80GHz.