US 2026/0142647 A1Published application

Acoustic wave filter and multiplexer

AssigneeMurata Manufacturing Co., Ltd.

InventorShiori ASAKAWA

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Abstract

An acoustic wave filter includes a filter circuit on a first path connecting an input terminal and an output terminal, and an additional circuit on a second path connected in parallel with the first path. The filter circuit includes series arm resonators on the first path. First and second nodes, which are connection points between the first and second paths, are provided on both outer sides of the series arm resonators, and the first node is closer to the input terminal than the second node. The series arm resonator, which is closer to the output terminal than the first node, includes one or more IDT electrodes, and an electrode finger pitch of the IDT electrode connected to the first node, among the one or more IDT electrodes, is smaller than the electrode finger pitches of the IDT electrodes of the other series arm resonators.

Claims20

Dependent claims

An acoustic wave filter comprising:

an input terminal;
an output terminal;
a filter circuit on a first path connecting the input terminal and the output terminal;
and
an additional circuit on a second path connected in parallel with at least a portion of the first path;
wherein
the additional circuit includes a longitudinally coupled acoustic wave resonator;
the filter circuit includes a plurality of series arm resonators on the first path and one or more parallel arm resonators on a path connecting the first path and ground;
each of the plurality of series arm resonators and the one or more parallel arm resonators includes an IDT electrode;
a first node and a second node, which are connection points between the first path and the second path, are provided on both outer sides of one or more of the series arm resonators on the first path;
the first node is closer to the input terminal than the second node;
one of the plurality of series arm resonators that is connected to the first node and is located closer to the output terminal than the first node includes one or more IDT electrodes;
and
an electrode finger pitch of one of the one or more IDT electrodes that is connected to the first node is smaller than an electrode finger pitch of IDT electrodes of other series arm resonators excluding the one of the plurality of series arm resonators.

11 more elements

An acoustic wave filter comprising:

an input terminal;
an output terminal;
a filter circuit on a first path connecting the input terminal and the output terminal;
and
an additional circuit on a second path connected in parallel with at least a portion of the first path;
wherein
the additional circuit includes a longitudinally coupled acoustic wave resonator;
the filter circuit includes a plurality of series arm resonators on the first path and one or more parallel arm resonators on a path connecting the first path and ground;
each of the plurality of series arm resonators and the one or more parallel arm resonators includes an IDT electrode;
a first node and a second node, which are connection points between the first path and the second path, are provided on both outer sides of one or more of the series arm resonators on the first path;
the first node is closer to the input terminal than the second node and is located between two of the series arm resonators that are adjacent to each other on the first path;
one of the two series arm resonators that is located closer to the output terminal than the first node includes one or more IDT electrodes;
and
an electrode finger pitch of one of the one or more IDT electrodes that is connected to the first node is smaller than an electrode finger pitch of an IDT electrode of a series arm resonator connected to the first node and located closer to the input terminal than the first node.

11 more elements

Dependencies are inferred from the claim text.