Optimization of Thermoelectric Microwave Power Sensors Based on Thin-Membrane Structure

In this work, the thermal conduction property of thermoelectric microwave power sensors is researched. The fabrication of the thermoelectric microwave power sensor consists of a front side and a back side processing using GaAs Monolithic microwave integrated circuit (MMIC) process and MEMS technology. An isolation structure on the front side is designed to prevent the thermal conduction from the resistor to the Coplanar waveguide (CPW). A thin-membrane on the back side is designed to prevent the thermal conduction from the resistor to the substrate. For the microwave power sensor without an isolation structure, the sensitivity is about 0.138, 0.136, 0.132, 0.115 and 0.111mV/mW at 8, 9, 10, 11 and 12GHz, respectively. For the microwave power sensor with an isolation structure, the sensitivity is about 0.142, 0.139, 0.135, 0.117 and 0.115mV/mW at 8, 9, 10, 11 and 12GHz, respectively. As a result, the higher thermal conduction efficiency and the higher sensitivity are obtained for the optimized thermoelectric microwave power sensors.