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A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure
Key Laboratory of Micro/Nano Systems for Aerospace, Ministry of Education, Northwestern Polytechnical University, Xi'an 710072, China
Shaanxi Province Key Laboratory of Micro and Nano Electro-Mechanical Systems, Northwestern Polytechnical University, Xi'an 710072, China
* Author to whom correspondence should be addressed.
Received: 20 September 2013; in revised form: 19 November 2013 / Accepted: 28 November 2013 / Published: 10 December 2013
Abstract: A novel resonant pressure sensor with an improved micromechanical double-ended tuning fork resonator packaged in dry air at atmospheric pressure is presented. The resonator is electrostatically driven and capacitively detected, and the sensor is designed to realize a low cost resonant pressure sensor with medium accuracy. Various damping mechanisms in a resonator that is vibrating at atmospheric pressure are analyzed in detail, and a formula is developed to predict the overall quality factor. A trade-off has been reached between the quality factor, stress sensitivity and drive capability of the resonator. Furthermore, differential sense elements and the method of electromechanical amplitude modulation are used for capacitive detection to obtain a large signal-to-noise ratio. The prototype sensor chip is successfully fabricated using a micromachining process based on a commercially available silicon-on-insulator wafer and is hermetically encapsulated in a custom 16-pin Kovar package. Preliminary measurements show that the fundamental frequency of the resonant pressure sensor is approximately 34.55 kHz with a pressure sensitivity of 20.77 Hz/kPa. Over the full scale pressure range of 100–400 kPa and the whole temperature range of −20–60 °C, high quality factors from 1,146 to 1,772 are obtained. The characterization of the prototype sensor reveals the feasibility of a resonant pressure sensor packaged at atmospheric pressure.
Keywords: pressure sensor; resonant sensor; micromachining; micro resonator; atmospheric pressure; quality factor
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MDPI and ACS Style
Ren, S.; Yuan, W.; Qiao, D.; Deng, J.; Sun, X. A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure. Sensors 2013, 13, 17006-17024.
Ren S, Yuan W, Qiao D, Deng J, Sun X. A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure. Sensors. 2013; 13(12):17006-17024.
Ren, Sen; Yuan, Weizheng; Qiao, Dayong; Deng, Jinjun; Sun, Xiaodong. 2013. "A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure." Sensors 13, no. 12: 17006-17024.