Fabrication of a 77 GHz Rotman Lens on a High Resistivity Silicon Wafer Using Lift-Off Process

Frequency-Modulated Continuous-Wave (FMCW) radar sensors based on analog or digital beamforming technology have been proven to be effective for avoidance of automotive collision or mitigation of collision damage. Investigation shows that instead of using microelectronic based analog or digital beamforming engines, if Rotman lens type passive beamformers can be used, the signal processing time as well as power consumption, size, integration complexity, and system building cost will be reduced significantly.

This paper presents the design procedure of the Rotman lens at mm-frequency range followed by 3D full wave simulation results. Proposed fabricated and tested silicon based Rotman lens is a potential to use in a low cost 77 GHz automotive radar.