Method of optimizing input impedance of surface acoustic wave filter

Abstract

Methods of designing band-pass filters and filters are disclosed. A baseline filter design meeting first design criteria may be established, the baseline filter design including a plurality of series surface acoustic wave resonators and a plurality of shunt surface acoustic wave resonators, each surface acoustic wave resonator having a respective resonant frequency. A performance metric based on an input impedance of the baseline filter design over a pass band may be determined. One or more alternate filter designs may be established and respective performance metrics determined, each alternative filter design established by reordering the resonant frequencies of two or more of the plurality of series surface acoustic wave resonators and/or two or more of the plurality of shunt surface acoustic wave resonators. A final filter design may be selected from the baseline design and the one or more alternate filter designs based on the respective performance metrics.