Patent ID: 11863162
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A filter comprising:
a pair of input/output terminals; and
one or more series resonators on a signal path connecting the pair of input/output terminals; wherein
each of the one or more series resonators includes an IDT electrode including a pair of comb-shaped electrodes on a substrate including a piezoelectric layer;
each of the pair of comb-shaped electrodes included in each of the one or more series resonators includes:
a plurality of electrode fingers extending in a direction orthogonal or substantially orthogonal to an acoustic wave propagation direction; and
a busbar electrode connecting one-side end portions of respective ones of the plurality of electrode fingers;

the IDT electrode of each of the one or more series resonators includes first electrode fingers, second electrode fingers, or both the first electrode fingers and the second electrode fingers, the first electrode fingers having a wider electrode finger width at an another-side end portion thereof than an electrode finger width at a center portion thereof, the second electrode fingers having a narrower or equal electrode finger width at an another-side end portion thereof than an electrode finger width at a center portion thereof;
the one or more series resonators includes one or more first series resonators;
in the IDT electrode of each of the one or more first series resonators, a direction connecting the another-side end portions of respective ones of the plurality of electrode fingers crosses the acoustic wave propagation direction; and
a first portion of the IDT electrode of each of the one or more first series resonators includes only the first electrode fingers, and a second portion and a third portion include only the second electrode fingers, the first portion being centrally located in the acoustic wave propagation direction, the second portion and the third portion being located on two sides of the first portion in the acoustic wave propagation direction.