Abstract: A heat sensor adapted to be brought into contact at a forward end with a product heated in a microwave oven whose temperature is to be measured comprises an elongate tubular body consisting a protective armor. This body is open at the forward end. A thermally conductive pad is disposed in the body at its open forward end and projects from the body. A heat-sensitive electrical component is incorporated in the pad. A cable extending along the inside of the body connects this component to a temperature measurement electrical circuit. The open forward end of the body and the pad contact the product conjointly.

Abstract: In a process for heating a substance which is substantially non-conducting electrically, at least one layer of the substance is disposed within a cavity between two plates of a metal which is a good conductor of electricity. Each plate lies in intimate contact with a respective one of the two larger surfaces of the substance. The resulting assembly of the substance and the plates is disposed at a predetermined minimum distance from the walls of the cavity. The substance is then exposed to electromagnetic radiation in the decimeter wavelength band at a predetermined power level and for a predetermined time.