Finite-Difference Time-Domain Techniques for Saw Device Analysis

In this paper, we show how the finite-difference time-domain method can be applied to the analysis of acoustic wave propagation through piezoelectric substrates. We discuss the need to impose the quasi-static approximation in order to satisfy the Courant time-sampling stability criterion and show how this approximation can be incorporated into the solution. We describe the problems that occur at the edges of the computational space and show that absorbing boundary conditions are needed to reduce spurious reflections. A graphical visualization of the acoustic wave propagation is given.