全对称谐振式压力传感器结构设计与仿真分析

提出了一种基于侧向驱动的全对称谐振式压力传感器结构.谐振结构采用侧向梳齿电容驱动,既保证了驱动力的线性特性,又由于本身的空气阻尼为滑膜阻尼,可以取得较高的品质因子.另外,设计的差分电容结构能进一步提高器件的检测灵敏度.经过ANSYS 10.0的仿真分析总结出谐振结构固有频率受结构参数影响的规律,确定了量程为0～550 kPa的谐振式压力传感器具体尺寸,其灵敏度达到了22.602 Hz/kPa；分析了温度对谐振结构固有频率的影响,得到-20～60℃下的热灵敏度温度系数为-1.8233 Hz/℃,为后续的温度补偿提供依据；最后通过分析谐振结构的频域响应特性,最终确定了传感器的频域特性曲线以及不同阻尼比下传感器的品质因子.为谐振式压力传感器真空封装的真空度选择提供参考.

Design and Simulation of Fully-symmetrical Resonant Pressure Sensor

A fully-symmetrical resonant pressure sensor based upon lateral drive is presented.Resonant structure adopts lateral comb capacitance drive,which can ensure the linear characteristic of driving force,and obtain higher quality factors because its air damping is a kind of slide-film damping.In addition,the differential capacitance structure of the design can further improve the detection sensitivity of device.According to the simulation analysis by ANSYS 10.0,the law by which the natural frequency of the resonator is influenced by the structural parameters can be summarized,the specific size of resonant pressure sensor with a range of 0 to 550 kPa is confirmed,and its sensitivity has reached up to 22.602 Hz/kPa;the impact of temperature on the natural frequency of the resonator is analyzed,knowing that the temperature coefficient of thermal sensitivity is-1.823 3 Hz/℃ and on the condition that temperature is-20 ℃ to 60 ℃,it provides basis for temperature compensation;Finally,based on the analysis on the frequency domain response characteristics of the resonator,ultimately the curve of frequency domain characteristics has been drawn up and the quality factors of sensor under different damping ratios are identified,it offers reliable reference for the choice of vacuum whose vacuum encapsulation of resonant pressure sensor.