On Enhancing the Sensitivity of Resonant Thermometers Based on Parametric Modulation

• Published in: Journal of microelectromechanical systems Vol. 30; no. 4; pp. 539 - 549
• Main Authors: Li, Chengxin, Xi, Jingqian, Wang, Yuan, Li, Fangzheng, Gao, Lu, Liu, Huafeng, Zhao, Chun, Tu, Liang-Cheng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Clamping; Energy transfer; Floors; Low noise; Mathematical model; MEMS thermometer; Modulation; Noise; Noise sensitivity; parametric modulation; Physics; Resonant frequency; resonant sensor; Sensitivity; Sensitivity enhancement; Stiffness; Temperature sensors; Thermometers; Vibration mode
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2021.3079442

In this paper, a new approach for enhancing the temperature sensitivity of a resonant MEMS thermometer, based on parametric modulation, is proposed. By periodically modulating the effective stiffness of a standard clamped-clamped beam (C-C beam), which is used as a proof-of-concept resonant MEMS thermometer, it is possible to create a virtual energy coupling between two fundamental modes of vibration. Through this energy transfer link, one particular mode (ideally high sensitivity) can be transferred to the vicinity of another mode (ideally low noise), thus creating an operating region where both increased sensitivity and low noise can be achieved. As a starting point, a sensitivity enhancement of up to 126% can be achieved in this particular study, while not deteriorating the readout noise floor. A noise floor of 19.7 <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> K/Hz 1/2 has been achieved. Potentially, this approach could be extended to other structures, or be used to decrease sensitivity to temperature fluctuations as well. [2021-0050]