Acoustic wave filter device, multiplexer, radio-frequency front-end circuit, and communication apparatus
AssigneeMurata Manufacturing Co., Ltd.
InventorKoji NOSAKA
Life of this patent
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Abstract
A filter includes a parallel arm resonator and an interdigital capacitor. The parallel arm resonator has an IDT electrode defined by first electrode fingers. The interdigital capacitor is defined by second electrode fingers and is connected to the parallel arm resonator. The electrode finger pitch of the second electrode fingers is smaller than the electrode finger pitch of the first electrode fingers. The film thickness of the second electrode fingers is smaller than the film thickness of the first electrode fingers. A self-resonant frequency of the interdigital capacitor is higher than a pass band of the filter.
Claims20
An acoustic wave filter device comprising:
- a first acoustic wave resonator including an InterDigital Transducer (IDT) electrode defined by a plurality of first electrode fingers;
- and
- an interdigital capacitor that is defined by a plurality of second electrode fingers and is connected to the first acoustic wave resonator;
- wherein
- a pitch of the plurality of second electrode fingers is smaller than a pitch of the plurality of first electrode fingers;
- a film thickness of the plurality of second electrode fingers is smaller than a film thickness of the plurality of first electrode fingers;
- and
- a self-resonant frequency of the interdigital capacitor is higher than a pass band of the acoustic wave filter device.
Dependencies are inferred from the claim text.