Performance Analyses Of MEMS Wine-glass Resonator In Inertial Environment

MEMS are a rapidly-developed field with increasing wide range of applications. MEMS sensor is the most widely used part of the apparatus. Of which, the MEMS resonant sensor has played an important role in the areas of automatic electronics,consumer electronics, biomedicine and navigation because of it’s excellent characteristics of high sensitivity, high-value of Q, low noise and low power consumption.This paper majorly researches on the characteristics of the MEMS Wine-Glass resonator under dynamic state. The quality factor is the most parameter of the resonator’s performance index. First, it introduced the physical significance of the QF and the four factors influence it, analyzed the most significant impact of the QF—the air damping loss.Then we discussed the reasons of the formation of air damping, showed squeeze-film damping is one of the major factors that influence the characteristics of the MEMS resonator.With ANSYS software and the method of finite factors analysis, we built models and made the simulations respectively for the three typical MEMS resonators:Double-clamped beam resonator, Wine-glass resonator and Square corner braced resonator. Results show that the offset of the Double-clamped beam resonator and the Square corner braced resonator is relatively little, and the influence to resonator can be ignored. But the offset of the Wine-glass resonator is large; its influence can not be ignored.We primarily studied the performances of the MEMS Wine-glass resonator based on the above analysis.First we built a disk-electrode model, elicited the computing formula of Q-value of the MEMS Wine-glass resonator, and analyzed the performances of the resonator under the dynamic-state.The analysis shows that Q just can reach 86.36% of the primary value when the distance between disk and the electrode drifted for 10% of the primary value. Then we discuss and analyze the choose of the anchor position, propose an idea of improvement of the resonator’s structure. This new method can increase Q. Meanwhile, we analyze the damping of the disk, derive the formula of the disk space within the squeeze film damping of MEMS Wine-glass resonator. The formula shows that reducing the disk radius and thickness, increasing the distance between the disc and the electrode can reduce the squeeze film damping and improve QF.We solve the Reynolds equation of the inner air of the MEMS Wine-glass resonator’s gap with the numerical methods, get the corresponding real pressure distribution within the gap through the MATLAB simulation, and then analyze air damping caused by the pressure distribution and it’s influence to the resonator QF.Analysis show that thickness and the thickness of the resonator disk just have slight influence on the pressure distribution. They can be ignored. The influence caused by the gap between disc and the electrode is more obvious.Research shows that when the amplitude of the disk is more than 70% of the gap, the change in air pressure within the gap is particularly significant, and its trend is increasing exponentially. This time, the damping caused by the air is also beginning to increase and the corresponding quality factor decrease.