[rmrfstar]

Does anyone have a white paper about corner reflectors and X-band SAR?

For what it's worth, the state very likely needs a warrant to use technologies capable of looking inside structures [1]. Not that the law applies to them, but hypothetically.

[1] https://en.wikipedia.org/wiki/Kyllo_v._United_States

[jcims]

Dunno, but if you look at some of the image gallery photos here, there's a very bright specular reflection from a number of vehicles. Police radar is right in this frequency range, so it would make sense of they have a retroreflective effect built into the paint on the plate.

https://www.sandia.gov/radar/imagery/index.html

Example: https://www.sandia.gov/radar/_assets/images/gallery/ka-band....

[__turbobrew__]

Maybe this? https://ieeexplore.ieee.org/abstract/document/6894586