Filter device, radio-frequency front-end circuit, and communication apparatus
AssigneeMurata Manufacturing Co., Ltd.
InventorKoji NOSAKA
Life of this patent
Estimating the term…
Abstract
A filter device includes a first filter and a second filter. The first filter and the second filter are disposed in parallel between a first terminal and a second terminal. A first passband of the filter device includes at least part of a second passband of the first filter. The first passband includes at least part of a third passband of the second filter. The second passband is narrower than the first passband. The third passband is narrower than the first passband. The third passband has a center frequency higher than a center frequency of the second passband. The first filter includes multiple elastic wave resonators and a first capacitive element. The first capacitive element is connected in parallel with the first elastic wave resonator.
Claims20
A filter device having a passband, the filter device comprising:
- a first filter and a second filter connected in parallel with each other between a first terminal and a second terminal, wherein
- the passband of the filter device includes at least part of a first passband of the first filter and at least part of a second passband of the second filter,
- the first passband and the second passband being narrower than the passband of the filter device,
- the second passband having a center frequency higher than a center frequency of the first passband, and
- the first filter includes
- a plurality of elastic wave resonators, and
- a first capacitive element connected in parallel with a first elastic wave resonator included in the plurality of elastic wave resonators.
A radio-frequency (RF) front-end circuit comprising:
- an amplifier circuit;
- and
- a filter device, the filter device including
- a first filter and a second filter connected in parallel with each other between a first terminal and a second terminal, wherein
- a passband of the filter device includes at least part of a first passband of the first filter and at least part of a second passband of the second filter, the first passband and the second passband being narrower than the passband of the filter device,
- the second passband having a center frequency higher than a center frequency of the first passband,
- the first filter includes
- a plurality of elastic wave resonators, and
- a first capacitive element connected in parallel with a first elastic wave resonator included in the plurality of elastic wave resonators, and
- the amplifier circuit is electrically connected to the filter device.
A communication apparatus comprising:
- an RF signal processing circuit that processes a radio-frequency (RF) signal transmitted and received by an antenna element;
- and
- a RF front-end circuit that transmits the radio-frequency signal between the antenna element and the RF signal processing circuit, the radio-frequency front-end circuit including
- an amplifier circuit, and
- a filter device, the filter device including
- a first filter and a second filter connected in parallel with each other between a first terminal and a second terminal, wherein
- a passband of the filter device includes at least part of a first passband of the first filter and at least part of a second passband of the second filter,
- the first passband and the second passband being narrower than the passband of the filter device,
- the second passband having a center frequency higher than a center frequency of the first passband,
- the first filter includes
- a plurality of elastic wave resonators, and
- a first capacitive element connected in parallel with a first elastic wave resonator included in the plurality of elastic wave resonators, and
- the amplifier circuit is electrically connected to the filter device.
Dependencies are inferred from the claim text.