Modeling of Differential Power Sensor Based on Seesaw Structure for Microwave Communication Application

Modeling of the differential power sensor based on microelectromechanical systems seesaw membrane is proposed in this paper. When the microwave power is applied, the center part of the membrane is pulled down toward the substrate, while two end parts are turned away from the substrate. The proposed model is based on the theory of simply supported membrane. The displacement of membrane and the capacitance change are both calculated as a function of the incident power. The microwave performance measurement shows that the return loss is less than -12.5 dB and the insertion loss is better than 1.5 dB over 1-10 GHz. The power response measurement demonstrates that the capacitance change magnitudes ΔC
_in
and ΔC
_out
both increase with the microwave power, which agrees with the proposed model. For ΔC
_in
, the measured sensitivity is close to 69.2 aF/mW at 1 GHz, 71.5 aF/mW at 5 GHz, and 66.3 aF/mW at 10 GHz, respectively. For ΔC
_out
, the sensitivity is close to 35.2 aF/mW at 1 GHz, 33 aF/mW at 5 GHz, and 27.6 aF/mW at 10 GHz, respectively.