Permittivity Determination Method for Multilayer Automotive Coatings for Radar Applications at 77 GHz

For highly automated driving functions, up to ten radar sensors must be installed without affecting the vehicle design. This is only possible if they are placed behind painted bumpers. In order to understand the effects of automotive coatings on radar, it is crucial to determine the relative permittivity of each coating layer. A holistic approach to achieve high precision when determining the relative permittivities of multilayer automotive coatings for radars operating at 76–77 GHz is presented. The method is applied to two different types of measurement setups utilizing a vector network analyzer (VNA) with corrugated horn antennas and an all-in-one quasi-optical free-space measurement solution.