| SAW devices containing slanted finger interdigital transducers (SFITs) show an inhomogeneous acoustic wave field in two directions, i.e. parallel as well as perpendicular with respect to the primary wave propagation direction. Commonly, SFITs are simulated by using one-dimensional coupling-of-modes (COM) theory. However, diffraction as well as refraction may significantly influence the device performance, hence, the calculation of the acoustic wave field becomes essential for accurate device modelling. In this paper we describe a quasi-2D (Q2D) COM approach for SAW diffraction calculation and demonstrate the calculation accuracy for a highly diffractive device produced on 112X-LiTaO3. |