振梁式负压传感器

Resonant Microcantilever Subatmospheric Press Sensor

对负压力的测量可采用各种真空计或者负压传感器 ,但其输出量大多为非电量或模拟式电量。本文制作了一种电热激励的微悬臂梁谐振式负压传感器 ,它利用随微悬臂梁振动的气体分子等效于增加微梁惯性质量的原理测量气压或气体密度。利用Navier Stokes方程和连续性方程计算作用在微悬臂梁上的惯性阻力 ,进而计算出谐振器谐振频率与气压的关系。分析表明 :增大梁的宽度 。

Subatmospheric pressure can be measured with various vacuum gauges or subatmospheric pressure sensors, but most of the output of these instruments is non electricity parameters or analog electrical signals. A micromechanical resonant sensor is reporeted in this paper. The sensitive element of this sensor is a electrothermally excited, piezoresistively detected microcantilever made by microelectronic and micromechincal technologies. The sensor applies the mass effect, that is, gas molecules vibrating with microcantilever increase the inert mass of the beam, to measure subatmospheric pressure or density of gas. With Navier Stokes eqution and continuity eqution, the relation of resonance frequency to subatmospheric pressure or density of gas is studied by calculation the inertial resistance imposing on the beam by surrounding air. The relation shows that the sensitivity of this sensor can be improved by increasing the width of beam and decreasing the length and thickness of beam.