FEM Simulation and Analysis of MEMS Based SAW Sensor to Detect Traces of Explosive Vapors

The identification of explosive compounds and associated materials plays a key role for both national security and public health, with sensor- based systems providing good portability and accuracy. This report discusses the simulation and evaluation of a chemoselective polymer coated surface acoustic wave sensor (SAW) for the detection of explosive gaseous aromatic compounds. The sensor is designed with a thin film of polyisobutylene (PIB) membrane on a Lithium Niobate, LiNbO3 substrate which was simulated using finite element method (FEM) in COMSOL Multiphysics software with an exposure of 2 ppm (parts per million) concentration of the gaseous analyte. The uniformity of ppm as concentration unit is maintained throughout the study to standardize the presentation of concentration values, with 2 ppm serving as a reference for evaluation. The simulation results have revealed that the exposure of gas has resulted in a significant shift in resonance frequency. Finally the device provided a linear behaviour of the resonance frequency shift when further simulated with varying concentrations of the gaseous analyte.