High Frequency Gas Detection With an Uncoated CMUT Array by Impedance Resonant Frequency Measurement

Abstract

This paper shows for the first time the ability to detect different gases by tracking the impedance of an uncoated silicon nitride capacitive micromachined ultrasonic transducer (CMUT) array at the anti-resonant frequency. The principle of this chemical detection is based on the influence of a physical property of the gas (the mass density) on the resonant properties of the CMUTs. In this paper, we present results for carbon dioxide and hydrogen detection. Potential applications of such sensor include long term gas monitoring or fast response gas sensing for gas leakage detection.