Double mode surface acoustic wave filter e.g. longitudinal coupled resonator filter, has transducer arrangement exhibiting symmetry of density with respect to transversal axis/point of symmetry with respect to center point of arrangement

摘要

The filter has a transducer arrangement with three transducers (W1, W21) including electrode fingers (EF1-EF5). The transducer (W1) is arranged in an acoustic path between the other two transducers, where the acoustic path is limited by two reflectors. The arrangement exhibits symmetry of density with respect to a transversal symmetrical axis or a point of symmetry with respect to a center point of the arrangement.