High performance silicon based Rotman lens for automotive radar applications

Design and fabrication of a silicon based microstrip Rotman lens for use in automotive collision avoidance applications is presented. The lens has 3 beam ports, 5 array ports, 16 dummy ports, and beam steering angles of ±10 degrees. 3-D full wave simulation using XFDTD™ shows better than 8 dB return loss, less than 0.5 degrees beam to array phase error and sidelobes level of less than -12 dB. The lens is fabricated on a 200 μm thick high resistivity silicon wafer. A functional test of the lens is conducted in a 77 GHz radar setup and the test results show that the lens is working fine as designed.