Sensitivity Analysis of Lateral Field Excited Acoustic Wave Gas Sensors with Finite Element Method

概要

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In the last decade, there are increasing investigations on lateral field excited (LFE) acoustic wave sensors in biochemical liquid sensing applications due to their high sensitivity and simple fabrication. However, the research on this kind of sensor for gas detection is still awaited. This paper presents a theoretical modeling of the LFE acoustic wave gas sensor with a nanostrustured selective film for the first time. We developed this model by adopting a finite element software, COMSOL. Besides the eigenfrequency and frequency-response analyses, the sensitivities to the variations of mass density and electrical conductivity of the selective film caused from gas concentration were calculated. In the meantime, quartz crystal microbalance (QCM) sensors were also analyzed for comparison. Finally, the effect of geometry of the LFE gas sensor on the sensitivity was discussed. Results show that the LFE sensor exhibits larger sensing range and higher sensitivity to external electrical variation than the QCM sensor. This is because no shielding electrode exists on sensing surface of the LFE sensor, and hence the electric field can penetrate into the selective film. The simulation results provide useful guidelines for designing LFE acoustic wave gas sensors.
2011-07-25