1956 Earth vs The flying Saucers

[BIAD]

Ever notice the weapon they used to bring the Sacers down?

Here a photo with the caption ' Experimental radar White Sands 1947'

That always puzzled me. At Roswell in 1947, it was suggested the object that came down was the result of
mobile radar-testing and as you said, in the movie too the craft were disabled by radar technology mounted
on trucks.

What is it with radar that can have such an effect?
(Fantastic movie, by the way!)