Filter circuit and composite filter device
AssigneeMurata Manufacturing Co., Ltd.
InventorTakayuki Okude
Life of this patent
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Abstract
A filter circuit includes a plurality of first resonators provided in a series arm, a plurality of second resonators provided in a parallel arm, and at least one or more third resonators that are electrically connected in series with each other and are electrically connected in parallel with the first resonators in the series arm. An anti-resonant frequency of the third resonators is lower than an anti-resonant frequency of the second resonators. A combined capacitance of the at least one or more third resonators electrically connected in series with each other is smaller than an electrostatic capacitance of the second resonators.
Claims20
A filter circuit comprising:
- a plurality of first resonators provided in a series arm;
- a plurality of second resonators provided in a parallel arm;
- and
- at least one or more third resonators that are electrically connected in series with each other and are electrically connected in parallel with the plurality of first resonators in the series arm;
- wherein
- an anti-resonant frequency of the at least one or more third resonators is lower than an anti-resonant frequency of the plurality of second resonators;
- and
- a combined capacitance of the at least one or more third resonators electrically connected in series with each other is smaller than an electrostatic capacitance of the plurality of second resonators.
Dependencies are inferred from the claim text.