Acoustic gas sensing with weakly coupled mems resonators

Abstract

Most of the current gas sensors are individually developed and limited with the detectable gas species due to their material or wavelength dependent sensing technology. We propose an acoustic gas sensing method that utilizes the weak coupling between specialized MEMS resonators originating from the cavity resonance, for the first time. The method directly captures the cavity resonance with inherently strong SNR and can detect any gas. We achieve >7X sensitivity compared to the previously proposed damping and frequency based measurements. We demonstrate the coupling with cavity/no cavity experiments and show the successful sensor operation up to 95% CO2 concentration.