A line of microwave heater sensor chips from State of the Art, Inc. has been developed for a wide range of thermal management applications. Using platinum on alumina and oxidized silicon, the sensor chips are ideal for determining the thermal resistance of substrates and integrated circuits (ICs). The line includes the model TM365 with two thermal sensors in close proximity to the heater for extremely stringent temperature control, and the model TM364 single sensor with moderate temperature control. The self-heating of the sensors is below 4 mW/C. Both devices are designed for use to +250C.