Automotive radar / LIDAR behind reflective surfaces

A sensor assembly for detecting an object comprising:

• at least one electromagnetic source configured to emit electromagnetic waves;
• at least one electromagnetic receiver configured to receive the electromagnetic waves after reflecting from the object and corresponding with a detection of the object in proximity to said sensor assembly;
• a filter cover disposed adjacent to and covering said at least one electromagnetic source and said at least one electromagnetic receiver, the filter cover being transmissive to the electromagnetic waves and reflective to a visible light, thereby concealing said at least one electromagnetic source and said at least one electromagnetic receiver;
• wherein said filter cover is associated with an exterior surface of a vehicle, and wherein the exterior surface has an appearance of a metal;
• and
• wherein the filter cover comprises a reflective polarizer configured to transmit the electromagnetic waves polarized in a first direction and to reject the electromagnetic waves polarized in a second direction different than the first direction, and wherein visible light impinging on an external surface of the reflective polarizer is reflected as visible light having reflectance spectra matching reflectance spectra of the exterior surface of the vehicle so that the reflective polarizer has the appearance of the metal to a person viewing the reflective polarizer.