Acoustic wave device in trapezoidal mode

A coupled resonator filter, comprising a plurality of acoustic resonators arranged in a length direction, wherein each of the acoustic resonators comprises:

• a piezoelectric layer;
• and
• a plurality of interdigital electrode structures over the piezoelectric layer, the plurality of interdigital electrode structures being insulated from one another, wherein each of the plurality of interdigital electrode structures comprises:
• a plurality of first electrode fingers and a plurality of second electrode fingers extending in a width direction, the plurality of first electrode fingers and the plurality of second electrode fingers interleaved with one another along a length direction, the length direction being different from the width direction, wherein:
• at least one of the plurality of first electrode fingers or the plurality of second electrode fingers includes an edge portion between two ends of a respective electrode finger, a wave velocity of an acoustic wave propagating in the edge portion along the length direction is different from that outside of the edge portion;
• and
• the at least one of the plurality of first electrode fingers or the plurality of second electrode fingers is apodized with an apodization pattern.