A Wide-Range Resonant Pressure Sensor With Enhanced Sensitivity Based On An Indirect Coupling Scheme

In this paper, a novel resonant pressure sensor based on an indirect coupling scheme is presented. An in-house fabricated circular piezoelectric microelectromechanical system (MEMS) resonator is used. The device is mounted on top of the diaphragm, and pressure is subsequently applied to the diaphragm's bottom surface. Finite element analysis is conducted to comprehend stress-displacement coupling between the diaphragm and resonator and the resulting frequency shift caused by pressure. The first flexural mode with a frequency of 152.3 kHz is used for sensing pressure. The sensor exhibits an exceptional combination of high sensitivity and wide bandwidth. The device records a pressure sensitivity of 11021.07 ppm/bar over 0 to 10 bar. The sensor showcases minimal hysteresis error for multiple measurement cycles. Methods for hysteresis mitigation are also demonstrated. This work introduces a conceptual framework for pressure sensors that offer good mechanical robustness, high sensitivity, and readout stability throughout a wide range.