3D electrostatic field analysis of periodic two-dimensional SAW transducers with closed-form formulae

A 3-D field analysis method is developed for the analysis of the 2-D charge distribution in surface acoustic wave (SAW) transducers. The method employs a periodic Green´s function constructed by superposition of the potential responses of a set of single point sources. A modified inverse-capacitance matrix that describes the whole structure has been established. Discretization has to be performed only in the main period. To obtain a prescribed accuracy, generally only a few periods at the left and at the right side with respect to the main cell have to be included in the analysis. Computational results for interdigital transducer (IDT) structures or YZ-LiNbO₃ are presented. The influence of bus-bars, floating fingers, and the aperture on the charge distribution is demonstrated