stealth paint

[the head]

IIRC Ka band radar is the one that uses the Doppler effect
X and Y band are standard redar systems
and then you also have Laser which is fast and very accurate but doesn't funciton well in Rain, or heavy fog also Laser needs a rather flat surface (police using laser are taught to aim for your plates) which is why most laser diffusers (jammers) mount around your plate or near the center of the fron of your car.

You can reduce radar cross seciton for X and Y band radar units both of those types of radar waves can transmit unhindered through fiberglass, CF and urethane so the area of reflection on a car with non metallic body work on the front end will be reduced signifigantly also with the metallic pieces all at odd angles and nonstandard shapes the odds of getting a clean lock on speed are signifigantly diminishied