A filter is provided that includes a set of cascaded resonator stages coupled between a filter input and a first filter output, wherein the filter includes a second filter output coupled to an output of a first or an intermediate one of the set of cascaded resonator stages. Another filter includes a set of cascaded resonator stages coupled between a first filter input and a filter output, wherein the filter includes a second filter input coupled to an input of an intermediate or a last one of the set of cascaded resonator stages. Both filters are configured to apply a first filter frequency response to a first signal propagating via the set of cascaded resonator stages, and apply a second filter frequency response to a second signal propagating via a subset of one or more of the set of cascaded resonator stages.

A multiplexer includes first and second filters connected to a common terminal. The second filter has a pass band on a higher frequency side with respect to a pass band of the first filter. The first filter includes a series arm circuit, and a parallel arm circuit having a resonant frequency on a lower frequency side with respect to a frequency at a low frequency end of a pass band of the first filter, and the series arm circuit includes a series arm resonator having a resonant frequency in the pass band of the first filter and a series arm resonator that is electrically connected in parallel to the series arm resonator and that has a resonant frequency on a higher frequency side with respect to a frequency at a high frequency end of the pass band of the first filter.

A surface acoustic wave filter includes series and parallel arm resonance sections. The series arm resonance section is in a series arm. The parallel arm resonance section is in a parallel arm. The series arm resonance section includes one or more surface acoustic wave devices. Each surface acoustic wave device includes a first resonator group and a second resonator group. The first and second resonator groups are connected in parallel and include surface acoustic wave resonators. The first resonator group includes at least one surface acoustic wave resonator. The second resonator group includes a greater number of surface acoustic wave resonators than the at least one surface acoustic wave resonator in the first resonator group. The resonant frequency of the surface acoustic wave resonator in the first resonator group is higher than the resonant frequency of the surface acoustic wave resonators in the second resonator group.

An acoustic wave filter device includes a filter disposed on a substrate, a wall member disposed on the substrate and surrounding the filter, a cap member disposed on the wall member and bounding an internal space with the wall member; and a support member disposed on the cap member. The support member is disposed above the internal space and includes a bump disposed on the cap member.

A surface acoustic wave resonator includes first and second surface acoustic wave resonator connected in series, and a third surface acoustic wave resonator connected in series with the second surface acoustic wave resonator. Each of the first to third surface acoustic wave resonators includes a pair of comb-shaped electrodes in which electrode fingers of one of the comb-shaped electrodes and electrode fingers of the other one of the comb-shaped electrodes are alternately arranged. The second surface acoustic wave resonator has a lower ratio of a width of the electrode fingers to a pitch between the electrode fingers than the first and third surface acoustic wave resonators.

A filter includes a series-arm resonator connected on a path connecting input/output terminals, and first and second parallel-arm resonators connected between the same node on the path and ground. A resonant frequency of the second parallel-arm resonator is higher than a resonant frequency of the first parallel-arm resonator, and an anti-resonant frequency of the second parallel-arm resonator is higher than an anti-resonant frequency of the first parallel-arm resonator. Each of the first and second parallel-arm resonators includes an acoustic wave resonator including an IDT electrode. The IDT electrode in the second parallel-arm resonator has a higher duty ratio than the IDT electrode in the first parallel-arm resonator, where the duty ratio is the ratio of the width to the pitch of electrode fingers.

In order to pass a signal having a wide pass bandwidth with respect to a center frequency of a pass band, a surface acoustic wave device includes a first surface acoustic wave element provided with a first pass band; and a second surface acoustic wave element having a second pass band in a high frequency band compared with the first pass band of the first surface acoustic wave element, in which the first surface acoustic wave element and the second surface acoustic wave element have a common input terminal and a common output terminal, and a frequency of a high frequency side of the first pass band of the first surface acoustic wave element is partially overlapped with a frequency of a low frequency side of the second pass band of the second surface acoustic wave element.

An electro-acoustic transducer and an electro-acoustic component including an electro-acoustic transducer are disclosed. In an embodiment the transducer includes a first and a second bus bar, a plurality of electrode fingers and a plurality of two or more sub tracks, wherein each electrode finger is electrically connected to one of the bus bars, wherein each sub track extends along a longitudinal direction, wherein all sub tracks are arranged one next to another in a transversal direction, wherein at least a first of the sub tracks includes segments of the electrode fingers and has an associated sub track with segments of the electrode fingers, wherein the segments of the electrode fingers of the first sub track are shifted by a distance S=/2 along the longitudinal direction relative to the segments of the electrode fingers of the associated sub track, and wherein is an acoustic wavelength.

A band elimination filter includes a plurality of parallel resonators, each including a piezoelectric substrate and an IDT electrode on a surface of the piezoelectric substrate. The IDT electrode includes a pair of comb-shaped electrodes opposing each other, and the IDT electrode includes electrode fingers, a pitch of the electrode fingers being different between an end portion of the IDT electrode in a propagation direction of an elastic wave and a central portion of the IDT electrode different from the end portion.

A filter is provided that includes a set of cascaded resonator stages coupled between a filter input and a first filter output, wherein the filter includes a second filter output coupled to an output of a first or an intermediate one of the set of cascaded resonator stages. Another filter includes a set of cascaded resonator stages coupled between a first filter input and a filter output, wherein the filter includes a second filter input coupled to an input of an intermediate or a last one of the set of cascaded resonator stages. Both filters are configured to apply a first filter frequency response to a first signal propagating via the set of cascaded resonator stages, and apply a second filter frequency response to a second signal propagating via a subset of one or more of the set of cascaded resonator stages.