SOFTWARE FOR A MULTILAYERED SURFACE-ACOUSTIC-WAVE DEVICE BASED ON THEFINITE-ELEMENT METHOD AND COUPLING-OF-MODES THEORY

A software package that provides an interactive and graphical environm ent for the design and modeling of multilayered surface acoustic wave (SAW) devices is described. The software is based on the finite elemen t method (FEM) and the coupling-of-modes theory (COM). FEM is used to calculate the dispersion diagram of an infinite periodic array and the capacitance of one pair of interdigital transducers (IDTs). COM param eters are then determined using these calculated data. As a result of COM calculations, a CI-port circuit representation is obtained for bas ic device elements such as IDTs, grating or IDT reflectors and delay l ines. The frequency response of SAW devices composed of these elements can be systematically evaluated by cascading the (6-port; circuits. A s an example, a high frequency SAW filter with a ZnO/diamond/Si struct ure is designed.