Sensitivity of a surface acoustic wave based gas sensor: Design and simulation

This paper focus on the design analysis of acoustic wave based MEMS sensor to detect some volatile organic gases. The principle of mass loading on the sensing layer is used to sense the presence of volatile organic gases. Design and simulations were carried out by using COMSOL MULTIPHYSICS 4.3 based on finite element modelling (FEM) for analytical simulations. The resonant frequency of the SAW sensor was determined and simulations are carried out by exposing the sensor to 100 ppm of various volatile organic gases and analogous shift in resonant frequency for dichloromethane gas is determined. The reduction or decrement in the resonant frequency is considered for the exposure of volatile organic gases such as chloromethane, dichloromethane, tetrachloroethane, carbon tetrachloride and trichloroethylene. High sensitivity of about 2.28 Hz/ppm with good selectivity and linearity are observed with a very high resolution.