I think you're last comment is probably correct, a microwave is designed to heat up water hence the reason why your browner doesn't get very hot. The idea is that it's preheated then with the food cooking on the plate, the plate warms from heat transfer of the food, this then dries/seals the outer surface of the food giving the fried effect. As a microwave Engineer the only time i've seen browning trays work if when they're used in combination ovens (convection,griil+microwave) and the oven is preheated to above 150 degrees Celcius. Hope this is of any help.