A resonant high-pressure microsensor based on a composite pressure-sensitive mechanism of diaphragm bending and volume compression

Abstract

In this paper, a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent accuracy. The composite mechanism was explained, and the sensor structure was designed based on theoretical analysis and finite element simulation. An all-silicon resonant high-pressure microsensor with multiple miniaturized cavities and dual resonators was developed, where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pressure and the same characteristics at different temperatures, which can improve pressure sensitivities and realize temperature self-compensation by differential frequency output. The microsensor was fabricated by microfabrication, and the experimental results showed that the sensor had an accuracy of ±0.015% full scale (FS) in a pressure range of 0.1~100 MPa and a temperature range of −10~50 °C. The pressure sensitivity of the differential frequency was 261.10 Hz/MPa (~2523 ppm/MPa) at a temperature of 20 °C, and the temperature sensitivities of the dual resonators were −1.54 Hz/°C (~−14.5 ppm/°C) and −1.57 Hz/°C (~−15.6 ppm/°C) at a pressure of 2 MPa. The differential output had an outstanding stability within ±0.02 Hz under constant temperature and pressure. Thus, this research provides a convenient solution for high-pressure measurements because of its advantages, namely, large range, excellent accuracy and stability.

Graphene resonant pressure sensor with ultrahigh responsivity-range product

“…Advances in micromachining technologies have enabled the miniaturization of traditional pressure sensors [1,2]. Microscale pressure sensors not only offer economy of scale but also have better performance in terms of responsivity [3] (change in output per unit change in pressure), resolution [4] (minimum detectable change), and range [5]. Micro-pressure sensors employ a thin silicon diaphragm that deforms when subjected to a pressure difference across it [3][4][5].…”

“…Microscale pressure sensors not only offer economy of scale but also have better performance in terms of responsivity [3] (change in output per unit change in pressure), resolution [4] (minimum detectable change), and range [5]. Micro-pressure sensors employ a thin silicon diaphragm that deforms when subjected to a pressure difference across it [3][4][5]. The strain change due to the deformation can be measured by piezo-resistively * Author to whom any correspondence should be addressed.…”

“…The strain change due to the deformation can be measured by piezo-resistively * Author to whom any correspondence should be addressed. [3,4,[6][7][8], capacitively [9][10][11][12][13], optically [14][15][16] or by measuring the change in resonance frequency of a resonator fabricated on the diaphragm [5,17,18]. The piezoresistive and capacitive transduction schemes offer excellent responsivities over a short linear range [7,10].…”