A 3-D Equivalent Circuit Modeling Method for the CMOS Thermoelectric Microwave Power Sensor

In order to solve the problems of high complexity and insufficient accuracy in modeling methods for the thermoelectric microwave power sensors, a 3-D equivalent circuit model of a complementary metal oxide semiconductor (CMOS) thermoelectric microwave power sensor is proposed, which is based on the substrate. Various module division schemes are compared to research the influence of substrate division thickness on model accuracy. A gradient division scheme that balances modeling efficiency and model accuracy is obtained. The relative errors of the hot junction and cold junction temperatures compared to the simulation of maximum temperature difference are 3.7% and 1.0%, respectively. The CMOS thermoelectric microwave power sensor is designed and fabricated based on 0.18 μm CMOS technology. According to the measurement results, the sensor has a return loss of less than -20 dB at 8-12 GHz,which exhibits good microwave performance. The sensitivities of the sensor at 8 GHz, 10 GHz, and 12 GHz are 3.8 μV/mW, 3.26 μV/mW, and 2.77 μV/mW, respectively. The theoretical sensitivity value of the model is 3.82 μV/mW, which indicates the measurement results are basically consistent with the theoretical result. This work has certain reference value for the design of thermoelectric microwave power sensors.