Acoustic wave filter device
AssigneeMurata Manufacturing Co., Ltd.
InventorYasumasa TANIGUCHI
Life of this patent
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Abstract
An acoustic wave filter device includes plural filter circuits between an input terminal and an output terminal. Plural inductors are connected in series in a series arm that connects the input terminal and the output terminal, and plural first acoustic wave resonators are connected between the series arm and a ground potential. Each of the filter circuits includes at least one of the inductors and one of the first acoustic wave resonators. A second acoustic wave resonator in the series arm connects adjacent filter circuits. The acoustic wave filter device has a pass band lower than a trap band, steep attenuation characteristics in a range from the pass band to the trap band, and is capable of providing a large amount of attenuation in the trap band.
Claims20
An acoustic wave filter device having a trap band and a pass band lower than the trap band, the acoustic wave filter device comprising:
- a plurality of inductors connected in series in a series arm having and connecting an input terminal and an output terminal;
- and
- a plurality of first acoustic wave resonators connected between the series arm and a ground potential,
- wherein a plurality of filter circuits are arranged in a direction from the input terminal to the output terminal, each of the plurality of filter circuits being composed of at least one of the plurality of inductors and the first acoustic wave resonators connected between the ground potential and respective ends of the at least one of the plurality of inductors,
- the acoustic wave filter device further comprising a second acoustic wave resonator provided in the series arm, wherein in at least one of portions where the plurality of filter circuits are adjacent to each other, the adjacent filter circuits are electrically connected by the second acoustic wave resonator.
Dependencies are inferred from the claim text.