Theoretical and Experimental Investigation of Cascaded Microwave Power Sensor

The cascaded power sensor, including terminating-type one and capacitive-type one is modeled in this paper. The electric-heat-electric conversion model in the terminating-type power sensor is based on Fourier conduction equation, and the electric-force-electric conversion model in the capacitive-type power sensor is based on strain equation. Experiments are performed to verify the model. For the incident power from 1 to 100 mW, the measured sensitivity of the terminating-type is 0.124 mV/mW and the sensitivity of the model is 0.135 mV/mW. For the incident power from 100 to 150 mW, the sensitivity of the capacitive-type sensor is about 0.156 fF/mW, while the calculated sensitivity of the model is 0.165 fF/mW. The comparison demonstrates that the related error of the voltage is less than 9% and the related error of the capacitance change is less than 6%.