The receivers just aren’t that delicate, and by the time you’re in range to try something fancy and expensive you’re also in range to just throw something that explodes at the radar. Believe it or not explosives are insanely inexpensive for governments, especially compared to a death laser like you’re envisioning.

Not to mention your death laser is also throwing out huge amounts of the same radio waves that could lead a radiation tracking missile right up your nose.