Precise simulation of surface transverse wave devices by discrete Green function theory

The paper proposes a precise simulation method for devices employing surface-transverse-waves (STWs) which propagate under grating structure and possess strong dispersive nature. The method is based upon the coupling-of-modes (COM) theory, where four parameters required for the analysis, i.e., static capacitance, and self-coupling, mutual coupling and transduction coefficients are determined as a function of frequency by the discrete Green function theory. The method has applied to the simulation of STW resonator filters on quartz, and the result was in good agreement with experiments. It was shown that the passband shape as well as the resonance frequency are most dependent on the thickness and width of grating electrodes. This is because STWs on quartz with weak piezoelectric coupling are substantially guided close to the surface by mass-loading effect of the grating