Hybrid Integrated Antenna for Automotive Short Range Radar Applications at 79GHz

This paper discusses the feasibility of integrating antennas on silicon for millimeter wave automotive radars. Since radar specifications require high gain and directivity antennas, the radiating structures cannot be fully integrated on silicon because of the intrinsic low resistivity of the substrate. We therefore investigate hybrid solutions, combining both an on-silicon antenna array and a coupled focusing system. A folded slot antenna is used as a primary antenna. Two solutions have been considered in order to significantly improve the gain and efficiency. Silicon integrated antenna arrays are first discussed, considering additional low loss dielectric sheets. A focusing system is then analyzed by applying the Robieux theorem and hybrid simulation techniques combining electromagnetic simulators and coupling techniques to avoid any complex multi-scale electromagnetic problem. A 6.5 dBi gain is achieved for a 4times4 element array while a 24.5dBi value can be achieved with an appropriate focusing system. Simulations are proposed and we also discuss the hybrid simulation procedure used. The manufacturing structure is in progress and experimental results will be presented during the conference.