Investigation into surface acoustic wave sensor for DCM gas detection using COMSOL multiphysics

Surface acoustic wave (SAW) gas sensors are simulated and discussed for the detection of the Dichloromethane (DCM) volatile organic gases (VOC) gas. The simulation was performed using Comsol Multiphysics software which is a finite element tool employed for the model analysis. The gas sensor response is investigated employing five different piezoelectric substrates. Among the simulated piezoelectric substrates, LiNbO3 reports the highest resonance frequency of 855.467 MHz, corresponding to a total displacement of 5.08 x 10(-4 )mu m. The effect of sensitive polyisobutylene (PIB) thin sensing layer has been discussed along with optimization of the layer thickness. The ZnO substrate shows the least dependence on the thickness of the PIB sensing layer. Finally, the device is further simulated with the DCM gas concentration which gives corresponding frequency shift under various concentrations in the range from 10 ppm to 250 ppm. The obtained resonance frequency shift showed a linear proportionately to the DCM concentration.