FFT-based analysis of periodic structures in microacoustic devices

Periodic structures utilized as transducer or reflector elements play an im portant role in microacoustic wave devices. Such structures can be describe d using approximate analytical models. However, to obtain the accuracy requ ired for reliable device simulation, numerical methods have to be employed. In this contribution, we present an efficient numerical approach to calcul ate the dispersion curves associated with microacoustic modes propagating i n periodic structures; the method is demonstrated for the case of Love wave modes. The computational efficiency is related to the utilization of the F FT algorithm in a hybrid Method of Moments (MoM) /Mode-Matching analysis, F rom the obtained dispersion curves, characteristic parameters such as the s topband width can be obtained which can be used in a coupling-of-modes (COM ) model of the structure.