Design and simulation of fully-symmetrical resonant pressure sensor

Abstract

A fully-symmetrical resonant pressure sensor based upon lateral drive is presented, which can avoid stress concentration that arises from temperature or vacuum packaging. Unlike conventional driving method, resonant structure with laterally driven comb capacitance allows the linear characteristic of driving force and also obtains high quality factor for its slide-film air damping. Furthermore, the detection sensitivity of the device can be improved by using differential capacitance, which will reduce shared-frequency interference phenomenon at the same time. According to the FEM analysis, the structural parameters of resonant pressure sensor are optimized. Meanwhile, the pressure sensitivity of the sensor has designed to be 22.602 Hz/kPa for a 18 μm thick diaphragm over a pressure range of 550 kPa. From temperature simulation, the temperature coefficient of sensor is -1.8233 Hz/°C in the range of -20°C~60°C without any temperature compensation. Finally, the frequency domain characteristics have been confirmed and the quality factors of sensor under different damping ratios are identified, it offers reliable reference for the choice of vacuum in resonant pressure sensor packaging.