Surface acoustic wave filter and method for improved rejection

摘要

A SAW coupled resonator filter providing improved rejection outside the passband frequencies includes at least two filter tracks on a piezoelectric substrate with each track having a plurality of acoustically cascaded transducers disposed along a longitudinal axis of the filter track. At least one filter track includes signal pads driven in a differential mode or a balanced mode. The two tracks are electrically connected with crossover bridges crossing over connecting lines between the tracks such that voltages across the crossover bridges are approximately the same in magnitude but substantially out-of-phase. The connecting lines extend between opposing bus bars of split transducers within each of the filter tracks.