Network model versus COM description of SAW devices

A network model for SAW (surface acoustic wave) structures fabricated along arbitrary, and hence asymmetric, orientations is described. The model includes NSPUDT (natural single-phase unidirectional transducer) directions. From the predictions of this model for SAW gratings, the coupling-of-modes (COM) phenomenological description is evaluated. It is demonstrated the incremental COM description can be derived from the unit-cell-based network model. Analytical formulas are compared with those calculated from the network model, and simple explicit formulas for the ABCD matrix, and hence for the COM parameters that predict their dependence on frequency, material parameters, and geometrical parameters, are derived