Patent ID: 11962287
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 5:
6. An acoustic wave filter comprising:
a first input/output terminal and a second input/output terminal;
one or more series arm resonators along a path connecting the first input/output terminal and the second input/output terminal; and
a plurality of parallel arm resonators each between a node in the path and ground; wherein
each of the one or more series arm resonators and the plurality of parallel arm resonators includes an acoustic wave resonator that includes an IDT electrode on a substrate having piezoelectricity;
the IDT electrode includes a pair of comb-shaped electrodes each including a plurality of electrode fingers and a busbar electrode, the plurality of electrode fingers being in parallel or substantially in parallel to one another and extending in a direction that crosses an acoustic wave propagation direction, the busbar electrode connecting one-end portions of the electrode fingers of the plurality of electrode fingers;
of the plurality of electrode fingers, an electrode finger not connected to either one of the busbar electrodes of the pair of comb-shaped electrodes is a floating withdrawal electrode;
of all of the electrode fingers of the pair of comb-shaped electrodes, an electrode finger connected to a same busbar electrode to which electrode fingers on both sides thereof are connected is defined as a polarity-reversing withdrawal electrode;
of the plurality of parallel arm resonators, a first parallel arm resonator having a highest resonant frequency includes an IDT electrode including the polarity-reversing withdrawal electrode; and
of the plurality of parallel arm resonators, at least one of the parallel arm resonators other than the first parallel arm resonator includes an IDT electrode including the floating withdrawal electrode.