提出一种应用于微谐振式压力传感器的敏感结构,其一次敏感元件为矩形硅膜片,膜片的上表面架设有三个两端固支的硅谐振梁,间接感受压力作用,根据膜片上不同位置设置的硅谐振梁的固有频率对于压力变化有不同的变化规律的特点,实现对被测压力的差动输出检测。针对这种结构,建立被测压力与谐振梁固有频率的数学模型。设计实际尺寸参数进行计算分析,得出谐振梁的分布位置和几何参数对其振动特性的影响规律,给出了由差动输出解算压力的公式,验证了所提出的结构的设计思想和优化参数的可行性。
This paper proposes a pressure sensing structure with a square silicon diaphragm as its preliminary and direct sensing component and three silicon resonant beams as the final and indirect sensing units which are attached on the upper surface of the diaphragm. Natural frequen-cies of silicon resonant beams set at different locations of the diaphragm have different variations as the pressure changes, thus to attain the differ-ential output. For this structure, this study builds the mathematical model of the pressure and the natural frequencies. It designs actual size pa-rameter to make some simulations and calculations, obtains laws of the distribution position and features of the resonant sensing structure, gives the formula of calculating the pressure and validates the design thought and optimization parameters.