Method of optimizing input impedance of surface acoustic wave filter

A filter designed by a method, comprising:

• establishing a baseline filter design meeting first design criteria, 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;
• analyzing the baseline filter design to provide a performance metric related to an input impedance of the baseline filter design over a pass band;
• establishing one or more alternate filter designs, each of the one or more alternative filter designs derived from the baseline filter design 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;
• analyzing each of the one or more alternative filter designs to provide a respective performance metric related to an input impedance of each alternative filter design over the pass band;
• and
• selecting a final filter design from among the baseline filter design and the one or more alternate filter designs based on the respective performance metrics.