Surface acoustic wave device for wideband signal transmission e.g. bandpass filter for mobile radio device or data transmission system, has interdigital transducers with acoustic waves in edge tracks and center track having opposing phases

摘要

The surface acoustic wave device has 2 fan-shaped interdigital transducers (W1,W2) provided on a piezoelectric substrate, the acoustic path of each divided in the transverse direction into 2 edge tracks (RB1,RB2; RB3,RB4) and a center track (MB) between the edge tracks, with variation of the finger mean spacing and/or width in the edge tracks and/or the center track, so that the acoustic waves in the edge tracks and the center track have opposing phases.