Optimization of inner structure of fan-shaped SAW transducers

Abstract

An optimization procedure is proposed for improving selectivity of fan-shaped interdigital transducers (FIDT) weighted by assignment of polarities of individual electrodes. At the first stage, weighting functions for input and output FIDTs are chosen, according to which initial electrode structures are formed. At the main stage a more precise tuning of electrode polarity arrangement is performed to meet filter frequency response specifications in the best way. SAW filters with bandwidth of 2-50% and out-of-band rejection of 47-60 dB have been designed with using the described algorithm.