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Effects of Air Cavity in Dynamic Pressure Sensors: Experimental Validation

Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, USA
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Author to whom correspondence should be addressed.
Sensors 2020, 20(6), 1759; https://doi.org/10.3390/s20061759
Received: 17 February 2020 / Revised: 15 March 2020 / Accepted: 17 March 2020 / Published: 22 March 2020
(This article belongs to the Special Issue Intelligent Sound Measurement Sensor and System)
An air-backed diaphragm is the key structure of most dynamic pressure sensors and plays a critical role in determining the sensor performance. Our previous analytical model investigated the influence of air cavity length on the sensitivity and bandwidth. The model found that as the cavity length decreases, the static sensitivity monotonically decreases, and the fundamental natural frequency shows a three-stage trend: increasing in the long-cavity-length range, reaching a plateau value in the medium-cavity-length range, and decreasing in the short-cavity-length range, which cannot be captured by the widely used lumped model. In this study, we conducted the first experimental measurements to validate these findings. Pressure sensors with a circular polyimide diaphragm and a backing air cavity with an adjustable length were designed, fabricated, and characterized, from which the static sensitivities and fundamental natural frequencies were obtained as a function of the cavity length. A further parametric study was conducted by changing the in-plane tension in the diaphragm. A finite element model was developed in COMSOL to investigate the effects of thermoviscous damping and provide validation for the experimental study. Along with the analytical model, this study provides a new understanding and important design guidelines for dynamic pressure sensors with air-backed diaphragms. View Full-Text
Keywords: acoustic–structural interaction; pressure sensors; modal analysis; experimental design acoustic–structural interaction; pressure sensors; modal analysis; experimental design
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MDPI and ACS Style

Dong, Q.; Song, X.; Liu, H. Effects of Air Cavity in Dynamic Pressure Sensors: Experimental Validation. Sensors 2020, 20, 1759.

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