I’d just wear one of those foil-lined suits like Chuck from “Better Call Saul”. Your move, EM radiation.
Sure, foil will dissipate the energy as induction current generated heating. How much of that can a Reynolds Wrap covered rioter stand? The original unit was about 2MW with a range of about 600 meters.
NOAA built a smaller W-band unit for measuring hurricane generated sea spray from a low flight level hunter aircraft. Appears about the right scale for a home brew unit. Delivers about 1700 watt output from a tube final stage.
Here is a starting point:
https://psl.noaa.gov/spotlight/2013/pdf/spotlight-wBand-P3.pdf