Computational analysis of micro-acoustic structures using the finite element method

In this paper we demonstrate the influence of node density on simulation convergence and computation time when modelling micro-acoustic structures using the finite element method (FEM). Whilst various other less computationally intensive techniques exist for the analysis of micro-acoustic devices, many of these methods encounter significant deficiencies when attempting to model massy electrodes and additional substrate features such as protecting walls and sensing layers. Furthermore existing simulation methods incorrectly assume that the substrate is of infinite extent, whereas the FEM can account for finite dimensioned devices. This paper demonstrates that the FEM is capable of modelling these complex structures provided that the model is correctly constructed. To illustrate the benefits of using the FEM, a simplified surface acoustic wave (SAW) micro-acoustic device is simulated and the insertion loss characteristic obtained. We also illustrate the scalability of the coupled-field problem when using shared memory parallel (SMP) computing architectures and present strategies to decrease computation time.