Patent ID: 11863159
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An acoustic wave filter comprising:
a first series-arm resonator and a second series-arm resonator on a path connecting a first terminal and a second terminal; wherein
the first series-arm resonator has a lower anti-resonant frequency than any other series-arm resonator included in the acoustic wave filter;
the first series-arm resonator and the second series-arm resonator each include an interdigital transducer (IDT) electrode including a pair of comb teeth-shaped electrodes on a substrate including a piezoelectric layer;
electrodes of the pair of comb teeth-shaped electrodes of the first series-arm resonator and electrodes of the pair of comb teeth-shaped electrodes of the second series-arm resonator each include electrode fingers and a busbar electrode, the electrode fingers extending in a direction orthogonal or substantially orthogonal to a propagation direction of an acoustic wave, the busbar electrode connecting first ends of the electrode fingers to each other;
a direction in which second ends of the electrode fingers are aligned with each other crosses the propagation direction of the acoustic wave;
the electrode fingers of the IDT electrode of the first series-arm resonator and the electrode fingers of the IDT electrode of the second series-arm resonator each include an electrode-finger central portion and a wide portion located at the second end and being wider than the electrode-finger central portion; and
a length of the wide portion of each of the electrode fingers in the first series-arm resonator in the direction in which the electrode fingers extend is greater than a length of the wide portion of each of the electrode fingers in the second series-arm resonator in the direction in which the electrode fingers extend.