Multiplexer, radio-frequency front-end circuit, and communication device
AssigneeMurata Manufacturing Co., Ltd.
InventorYuichi Takamine
Life of this patent
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Abstract
A quadplexer includes a first filter and a second filter having a pass band frequency that is higher than a pass band frequency of the first filter. The first filter includes series resonators disposed on a first path and parallel resonators disposed on a path that connects the first path and a ground to each other. A direction that connects ends of a plurality of electrode fingers defining each resonator crosses an elastic wave propagation direction at a predetermined angle. The series resonator nearest to a common terminal does not include first electrode fingers, and the other series resonators include the first electrode fingers.
Claims20
A multiplexer comprising:
- a common terminal, a first terminal, and a second terminal;
- a first filter disposed on a first path that connects the common terminal and the first terminal to each other;
- and
- a second filter disposed on a second path that connects the common terminal and the second terminal to each other, the second filter having a pass band frequency that is higher than a pass band frequency of the first filter;
- wherein
- the first filter includes:
- two or more series resonators disposed on the first path;
- and
- one or more parallel resonators disposed on a path that connects the first path and a ground to each other;
- each of the two or more series resonators and the one or more parallel resonators includes an IDT electrode and a reflector that are provided on a substrate including a piezoelectric layer, the IDT electrode including a pair of comb-teeth electrodes;
- each of the pair of comb-teeth electrodes included in each of the two or more series resonators includes:
- a plurality of electrode fingers extending in a direction orthogonal or substantially orthogonal to an elastic wave propagation direction;
- and
- a busbar electrode that connects one end of each of the plurality of electrode fingers to one another;
- a direction passing through other ends of the plurality of electrode fingers crosses the elastic wave propagation direction at a predetermined angle;
- the IDT electrode included in each of the two or more series resonators includes at least one of a first electrode finger type including first electrode fingers and a second electrode finger type including second electrode fingers among the plurality of electrode fingers, each of the first electrode fingers having a width that is larger at the other end than at a central portion, each of the second electrode fingers having a width that is smaller at the other end than at a central portion or that is the same or substantially the same at both of the other end and the central portion;
- and
- a ratio of a number of the second electrode fingers to a number of the plurality of electrode fingers included in a series resonator nearest to the common terminal among the two or more series resonators is higher than a ratio of a number of the second electrode fingers to a number of the plurality of electrode fingers included in each of the other one or more series resonators among the two or more series resonators.
Dependencies are inferred from the claim text.