Frequency Drift Compensation in Mass-Sensitive Chemical Sensors based on Periodic Stiffness Modulation

Abstract

The successful compensation of frequency drift in a mass-sensitive chemical microsensor is demonstrated. The proposed compensation method uses a periodic stiffness modulation, generated by a second feedback loop, to monitor the microresonator's quality factor (Q-factor). The Q-factor is solely obtained from frequency measurements and monitored along with the measurand-induced frequency shift during normal closed-loop sensor operation. This simultaneous measurement of Q-factor and frequency shift enables the compensation of frequency drift induced by environmental disturbances using the extracted Q-factor. The feasibility of drift compensation has been demonstrated by implementing the compensation scheme into a closed-loop chemical sensing system and performing gas-phase chemical measurements.