Filter device, radio-frequency front-end circuit, and communication apparatus

A filter device having a first 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 first passband of the filter device includes at least part of a second passband of the first filter and at least part of a third passband of the second filter,
• the second passband and the third passband being narrower than the first passband of the filter device,
• the third passband having a center frequency higher than a center frequency of the second passband,
• the second filter includes
• a first parallel arm resonator connected between a grounding node and a first connecting node on a path from the first terminal via the second filter to the second terminal, and
• a second parallel arm resonator connected between the grounding node and a second connecting node on the path from the first terminal via the second filter to the second terminal, the second connecting node being different from the first connecting node, and
• under a condition that a value obtained by dividing a difference between an antiresonance frequency and a resonance frequency of each parallel arm resonator by the resonance frequency is defined as a fractional bandwidth, a fractional bandwidth of the first parallel arm resonator is different from a fractional bandwidth of the second parallel arm resonator.

A radio-frequency front-end circuit comprising:

• a filter device having a passband, the filter device having
• 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 second passband of the first filter and at least part of a third passband of the second filter,
• the second passband and the third passband being narrower than the passband of the filter device,
• the third passband having a center frequency higher than a center frequency of the second passband,
• the first filter includes a plurality of series arm resonators connected in series with each other in a path from the first terminal via the first filter to the second terminal,
• the plurality of series arm resonators include a first series arm resonator and a second series arm resonator, and
• under a condition that a value obtained by dividing a difference between an antiresonance frequency and a resonance frequency of each series arm resonator by the resonance frequency is defined as a fractional bandwidth, a first fractional bandwidth of the first series arm resonator is different from a second fractional bandwidth of the second series arm resonator;
• and
• an amplifier circuit electrically connected to the filter device.