[bcaa7f3a8bbc]

For detection, yes, it can be done by an extremely simple circuit. But you would need the raw I/Q sample data over a broad frequency range to perform a technical analysis to identify the nature of the microwave. Here's when a SDR comes handy.

[kurthr]

The LED just reveals power (detection of radiation over many visible orders of magnitude) ... it doesn't need to detect coherent I/Q, because I don't think neural effects are sensitive to phase either. Selectively cooking a brain would require relatively high power and beam forming, but not high data rate. Audio frequencies are visible (use multiple band pass filters if you like) .

You'd also want a controlled test source so you'd know if the attacker had burned it out.