Design and optimization of a novel resonant gauge pressure sensor

Resonant pressure sensors are widely used in high precision pressure measurement, but they are mainly focused on the measurements of absolute pressure at present. The fluctuation of atmospheric pressure disturbs the accuracy of gauge pressure sensor. Therefore, a resonant gauge pressure sensor with a double-ended tuning fork resonator is proposed based on wafer level anodic bonding method. To sense the gauge pressure with high accuracy when the resonator is set inside the diaphragm, a novel composite diaphragm structure is proposed with the glass vacuum package layer involved in the pressure-lead diaphragm deflection. The resonator is laterally electromagnetically driven to symmetry mode and electromagnetically detected. With finite element analysis simulation, the effects of several key factors on the measuring accuracy of gauge pressure sensor are discovered and optimized. Research results show that the frequency detection error caused by the fluctuation of atmospheric pressure is reduced by changing the area of bonded area above the resonator and the glass thickness. The simulated non-linearity of proposed sensor after quadratic polynomial fitting is less than 0.01% FS with the pressure range of 0-2.5 MPa, and its measuring sensitivity is up to 3996.6 Hz/MPa.