Microwaves operate at 2.4ghz and I would post an RF safety calculator but that is for antenna radiation... leakage from a microwave will be much smaller. I posted the wrong spectrum analyzer up above, that one is good to 900 mhz only, to low for microwave ovens. This one and a laptop and free software go to 4.4ghz so it covers microwave ovens https://www.ebay.com/itm/Simple-Spec...72.m2749.l2649