IDT-based acoustic devices use electro mechanic coupling in piezoelectric media to excite propagating waves. Due to the sensitivity of media's wave velocity to temperature, stress and mass loading, these acoustic devices are used as sensors. Such acoustic devices enable passive and wireless detection making them especially good candidates for sensing application in harsh environment. However, the design of acoustic wave sensors is highly iterative because of the large number of parameters to be optimized in addition to the complex electro mechanic interactions.
To shorten development time, several numerical and analytical methods have been developed. The model we present here is based on Finite Element analysis. Because of the high aspect ratio of the geometry, a complete FE simulation of the device would be very time consuming, therefore using the periodicity of the structure, the model is simplified (reduced) to a single pair of fingers. This model enables to compute the harmonic admittance and extract parameters that are used afterward to simulate actual devices.