How are microwaves or higher frequency waves detected/measured?
Microwaves and higher frequency waves can be detected as any radio waves. One way is to have antenna which when exposed to a field builds and voltage and current signal at the same frequency as the incoming wave. The voltage/current signal is filtered so only the frequency components of the signal around the intended frequency are transmitted. Then this signal is rectified to produce a DC signal which is measured. There are several other ways to do this but this is the most common.
