A New RF MEMS Power Sensor Based on Double-Deck Thermocouples With High Sensitivity and Large Dynamic Range

Abstract

This letter reports a new RF MEMS power sensor based on double-deck thermocouples with high sensitivity and a large dynamic range. In order to improve RF sensing capability and sensitivity, the double-deck thermocouples and a MEMS substrate membrane are carefully designed. The proposed RF MEMS power sensor is fabricated by GaAs monolithic microwave integrated circuit (MMIC) process coupled with MEMS technology. Experimental result shows that the output thermovoltage of the device has inherent RF-dc linearity with the power from 1 to 500 mW. And the measured return loss is less than -28.6 dB at 1-20 GHz, which exhibits excellent matching characteristics. Moreover, at 8, 10, and 12 GHz, the measured sensitivities are 133.2, 124.3, and 116.8 μV/mW, respectively. Compared with a traditional thermoelectric power sensor, the sensitivity and the dynamic range of the proposed RF MEMS power sensor are increased by approximately 61% and 2.5 times, respectively. The research work can be considered as an incremental improvement of the state of the art (higher power sensing capability and sensitivity) as RF power sensing using double-deck thermocouples.