A band pass filter includes a longitudinally coupled resonator elastic wave filter on a piezoelectric substrate and parallel arm resonators at parallel arms, each connected between a series arm connecting an antenna terminal and a receiving terminal and one of ground terminals. The parallel arm resonators include a first parallel arm resonator having the highest resonance frequency among the parallel arm resonators and a second parallel arm resonator. A second ground terminal that is one of the ground terminals connected to the second parallel arm resonator and a third ground terminal that is one of the ground terminals connected to the longitudinally coupled resonator elastic wave filter are connected to each other. A first ground terminal that is one of the ground terminals connected to the first parallel arm resonator is not connected to the second or third ground terminals.

A multiplexer includes a transmission filter and a reception filter that are connected to a common terminal, and a cancellation circuit that is connected to the common terminal and a node on a transmission path and that offsets a component in a certain frequency band flowing through the transmission filter. The cancellation circuit includes a capacitive element connected to the common terminal, and a longitudinally-coupled resonator including a first end connected to the capacitive element and a second end connected to the node with no capacitive element interposed therebetween. An impedance in a reception band when viewing the cancellation circuit from the common terminal side is higher than an impedance in the reception band when viewing the cancellation circuit from the node side.

A high-frequency module includes a longitudinally coupled surface acoustic wave filter and a low-noise amplifier that is connected to the surface acoustic wave filter. The input impedance of the surface acoustic wave filter connected to the low-noise amplifier differs from the output impedance thereof. On a Smith chart, the output impedance in the pass band of the surface acoustic wave filter is present in a region between a first output impedance and a second output impedance, the first output impedance being the output impedance of the surface acoustic wave filter where a gain of the low-noise amplifier is maximum, the second output impedance being the output impedance of the surface acoustic wave filter where a noise figure of the low-noise amplifier is minimum.

In a splitter, a first duplexer including a first transmit filter and a first receive filter at a first antenna terminal and a second duplexer including a second transmit filter and a second receive filter at a second antenna terminal are connected to each other. A second transmit band of the second transmit filter and a second receive band of the second receive filter are positioned in a frequency range between a first transmit band of the first transmit filter and a first receive band of the first receive filter. Each of the second transmit filter and the second receive filter of the second duplexer includes an elastic wave filter. The elastic wave filter includes a high acoustic velocity film defining a high acoustic velocity member, a low acoustic velocity film through which transversal waves propagate at a lower velocity than those propagating through the high acoustic velocity film, a piezoelectric film disposed on the low acoustic velocity film, and IDT electrodes disposed on the piezoelectric film, which are stacked on each other in this order.

An elastic wave device includes first and second longitudinally coupled resonator elastic wave elements aligned on a piezoelectric substrate. A second reflector of the first longitudinally coupled resonator elastic wave element and a third reflector of the second longitudinally coupled resonator elastic wave element are adjacent to each other in an elastic wave propagation direction. A ground interconnection extends in a direction intersecting with the elastic wave propagation direction and in a region between the second reflector and the third reflector. A gap in one portion of the ground interconnection includes a different acoustic velocity portion where an acoustic velocity is different from an acoustic velocity in another portion of the ground interconnection.

A band pass filter includes a longitudinally coupled resonator elastic wave filter on a piezoelectric substrate and parallel arm resonators at parallel arms, each connected between a series arm connecting an antenna terminal and a receiving terminal and one of ground terminals. The parallel arm resonators include a first parallel arm resonator having the highest resonance frequency among the parallel arm resonators and a second parallel arm resonator. A second ground terminal that is one of the ground terminals connected to the second parallel arm resonator and a third ground terminal that is one of the ground terminals connected to the longitudinally coupled resonator elastic wave filter are connected to each other. A first ground terminal that is one of the ground terminals connected to the first parallel arm resonator is not connected to the second or third ground terminals.

An acoustic wave device includes a first acoustic wave filter, a first conductor portion between the first acoustic wave filter and a second acoustic wave filter and connected to a second functional conductor portion of the second acoustic wave filter. The first acoustic wave filter includes a signal electrode on a second main surface of a first piezoelectric substrate and connected to the first conductor portion, a ground electrode on the second main surface of the first piezoelectric substrate, and a second conductor portion connected to the ground electrode. The ground electrode overlaps a first functional conductor portion and does not overlap the signal electrode in a thickness direction of the first piezoelectric substrate. The second conductor portion is located between first and second main surfaces of the first piezoelectric substrate and spaced apart from the first main surface.

Aspects of this disclosure relate to an acoustic wave resonator having at least two resonant frequencies. An acoustic wave filter can include series acoustic wave resonators and shunt acoustic wave resonators together arranged to filter a radio frequency signal. A first shunt resonator of the shunt acoustic wave resonators can include an interdigital transducer electrode and have at least a first resonant frequency and a second resonant frequency. Related acoustic wave resonators, multiplexers, wireless devices, and methods are disclosed.

An acoustic wave sensor device comprises a quartz material layer surface; arranged along a first axis, a first interdigitated transducer disposed over the planar surface of the quartz material layer, a first reflection structure disposed over the planar surface of the quartz material layer, and a second reflection structure disposed over the planar surface of the quartz material layer; and arranged along a second axis, a second interdigitated transducer disposed over the planar surface of the quartz material layer, a third reflection structure disposed over the planar surface of the quartz material layer, and a fourth reflection structure disposed over the planar surface of the quartz material layer; and wherein the first axis and the second axis are inclined to each other by a finite angle.

A filter device includes at least one parallel arm resonator and series arm resonators including at least one first series arm resonator and at least one second series arm resonator being different from each other, a resonant frequency of the first series arm resonator is higher than a pass band of the filter device, the second series arm resonator has a series connection configuration in which at least two series arm resonators are connected in series to each other, anti-resonant frequencies of the at least two series arm resonators are different from each other, and the resonant frequency of the first series arm resonator is between the anti-resonant frequency of the series arm resonator on a lowest frequency side of the second series arm resonator and the anti-resonant frequency of the series arm resonator on a highest frequency side of the second series arm resonator.