An immersive resonant sensor with microcantilever for pressure measurement

Abstract

A micro electromechanical systems (MEMS) resonant sensing chip with microcantilever has been developed to measure gas pressure by immersing it in gaseous environment. The microcantilever was designed to sense surrounding gas molecules loading, owing to the gas density sensitive to the pressure, then the resonant frequency shifts of sensing chip were induced under different pressures. Especially, the sensing chip featuring no diaphragm realized embedded package and installation for the immersive measurement. The resonance response of the sensing chip for target pressure was theoretically analyzed and simulated, and a packaged pressure sensor with the proposed sensing chip was tested under flexural and torsional modes of the microcantilever. The experimental results proved that the proposed sensor had preferable measuring performance under the torsional mode with the RSS (root sum square) accuracy of 0.21%FS in the working range of 10–560 kPa. The temperature compensation was presented to alleviate the temperature disturbance for the sensor, and the maximum deviation of the frequency was 59 ppm over the full pressure and the temperature range of 26–55 ℃. The proposed sensing chip is potentially a better choice for pressure sensors with measurement demand for immersive gas pressure.