Coupling-of-modes modelling for fast and precise simulation of leaky surface acoustic wave devices

The paper proposes a mathematical model for leaky surface acoustic wave (LSAW) device simulation. The model simply treats the dispersion arising from reflection, mass-loading, piezoelectric and energy-storing effects. The parameters characterising the model are determined by numerically fitting to the result obtained by the discrete Green function. From the model, two coupling-of-modes (COM) parameters describing LSAW dispersion can readily be derived in a closed form. Another two parameters representing electrical properties are assumed to be constant for simplicity. Coupling-of-modes simulation based upon the model is carried out for LSAW devices on 36°YX-LiTaO₃. The result is in good agreement with experiments, clearly showing the effectiveness of the proposed model