Abstract: A filter device includes a filter circuit including first and second terminals and series arm resonators along a series arm connecting the first terminal and the second terminal, and an additional circuit connected in parallel at least some of the series arm resonators. The additional circuit includes first, second, and third interdigital transducer electrodes. The first interdigital transducer electrode is connected to a first node at one end portion of a series arm resonator having a lowest anti-resonant frequency of the series arm resonators, the second interdigital transducer electrode is connected to a second node having a potential different from a potential of the first node, the third interdigital transducer electrode is connected to a third node having a potential different from the potentials of the first and second nodes, and the first and second nodes are closer to the first terminal than the third node.

Abstract: A filter device includes a piezoelectric substrate, and multiple serial arm resonators and at least one parallel arm resonator on the piezoelectric substrate. First serial arm resonators of the multiple serial arm resonators include a silicon oxide film with a relatively large film thickness. Another of the multiple serial arm resonators is a second serial arm resonator including a silicon oxide film with a relatively small film thickness. Anti-resonant frequencies of the first serial arm resonators are lower than that of the second serial arm resonator. An aspect ratio is determined by a ratio of an intersecting width of electrode fingers of an IDT electrode relative to a number of electrode fingers of the IDT electrode. Aspect ratios of the first serial arm resonators are higher than that of the second serial arm resonator.

Abstract: 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.

Abstract: A high frequency filter includes a filter circuit portion on a first path between first and second signal electrodes, and an additional circuit portion on a second path parallel or substantially parallel to at least a portion of the first path. The filter circuit portion includes series arm resonators, parallel arm resonators, and an inductor on a path connecting a portion or all of parallel arm resonators and a ground. Acoustic wave resonators of the additional circuit portion include first and second electrodes. The first electrodes are connected to the second path. The second electrodes are connected to a connection conductor on a path connecting a portion or all of the parallel arm resonators and the inductor.

Abstract: A multiplexer includes a common terminal, a first filter connected to the common terminal, a wiring line connecting the common terminal and the reception filter to each other, a second filter connected to a connection node on the wiring line, a third filter connected to a connection node on the wiring line, a wiring line connecting the connection node and the transmission filter to each other, a wiring line connecting the connection node and the first filter to each other, and an inductor connected between a wiring region of the wiring line that extends from the connection node to the first filter and the ground or between the wiring line and the ground. The length of a portion of the wiring line extending from the common terminal to the connection node is longer than the length of a portion of the wiring line extending from the common terminal to the connection node.

Abstract: A multiplexer includes an antenna terminal, an inductance element, and a transmission-side filter and a reception-side filter connected to the antenna terminal. The transmission-side filter has a first pass band, and the reception-side filter has a second pass band. The reception-side filter is connected to the antenna terminal through the inductance element. A center frequency of the second pass band is higher than a center frequency of the first pass band. The reception-side filter includes parallel arm resonance portions including a first parallel arm resonance portion connected closest to the inductance element. An electrostatic capacitance of the first parallel arm resonance portion is larger than an electrostatic capacitance of any other parallel arm resonance portions.

Abstract: An acoustic wave filter includes at least one serial arm resonance circuit on a path connecting input/output terminals, and at least one parallel arm resonance circuit between a node on the path and a ground, in which each of the at least one serial arm resonance circuit and the at least one parallel arm resonance circuit includes an acoustic wave resonator, a first parallel arm resonance circuit of the at least one parallel arm resonance circuit includes a bridging capacitor connected in parallel to the acoustic wave resonator, an anti-resonant frequency of the first parallel arm resonance circuit is positioned on a higher-frequency side than the pass band, and a resonant frequency of a first serial arm resonance circuit of the at least one serial arm resonance circuit is positioned on a lower-frequency side than the anti-resonant frequency of the first parallel arm resonance circuit.

Abstract: A filter includes a substrate including a piezoelectric layer, and first and second signal electrodes, a filter circuit on a first path connecting the first signal electrode and the second signal electrode, and an additional circuit on a second path connected in parallel with at least a portion of the first path. The filter circuit includes one or more resonators and a main wiring line on the substrate, and the additional circuit includes a sub-wiring line and an acoustically coupled resonator on the substrate, the acoustically coupled resonator including acoustic wave resonators adjacent to each other. An insulating film is between the substrate and the sub-wiring line. A dielectric constant of the insulating film is smaller than a dielectric constant of the piezoelectric layer.

Abstract: A filter device includes a series arm connecting input and output terminals. Parallel arms branch from the series arm to a ground terminal. The parallel arms include first and second parallel arms branching from portions of the series arm. The first and second parallel arm resonators are respectively provided in or on the first and second parallel arms. The parallel arm resonators each include an IDT electrode including electrode fingers. Each IDT electrode includes an overlap region. A number of pairs of electrode fingers of the IDT electrode in the first parallel arm resonator is greater than a number of pairs of electrode fingers of the IDT electrode in the second parallel arm resonator. An overlap width of the IDT electrode in the first parallel arm resonator is narrower than the overlap width of the IDT electrode in the second parallel arm resonator.

Abstract: A filter device includes a filter between an input terminal and an output terminal, and an additional circuit connected in parallel with the filter between the input terminal and the output terminal. The additional circuit includes at least two longitudinally coupled resonators connected in parallel with each other and including longitudinally coupled resonators, and at least one capacitance element between the input terminal and the at least two longitudinally coupled resonators or between the output terminal and the at least two longitudinally coupled resonators. The average pitch of a plurality of electrode fingers of IDT electrodes of the longitudinally coupled resonator and the average pitch of a plurality of electrode fingers of IDT electrodes of the longitudinally coupled resonator are different from each other.

Abstract: A multiplexer includes a filter on a first path connecting a common terminal and an input/output terminal, and a second filter on a second path connecting the common terminal and a second terminal, the second filter having a passband that overlaps a generation frequency of Rayleigh wave ripples in the filter. The filter includes series arm resonators on the first path and a parallel arm resonator, the series arm resonators and the parallel arm resonator utilize an SH wave as a main mode, and a number of electrode finger pairs of the series arm resonator is fewest among numbers of electrode finger pairs of the series arm resonators.

Abstract: A filter includes a first filter circuit and an additional circuit. The first filter circuit includes a resonator electrode and a main wire. The main wire includes first and second metal films, the second metal film being in contact with the first metal film. The additional circuit includes an IDT electrode group including IDT electrodes and a sub-wire connecting the IDT electrode group to the first filter circuit. At least a portion of the sub-wire includes a third metal film connected to the IDT electrode group. The third metal film is covered with a fourth metal film with an insulating layer interposed therebetween, the insulating layer being provided on the third metal film. The fourth metal film is connected to a ground terminal on a substrate.

Abstract: A multiplexer includes a first filter and a second filter with a lower pass band than that of the first filter. A longitudinally coupled acoustic wave resonator of the first filter includes an interdigital transducer electrode group of interdigital transducer electrodes having an asymmetric shape with respect to a center line that passes through a center of the interdigital transducer electrode group and is perpendicular or substantially perpendicular to an acoustic wave propagation direction. The interdigital transducer electrodes connected to a first path on a common terminal side when seen from the longitudinally coupled acoustic wave resonator have a smaller aggregate average of electrode finger pitches of the interdigital transducer electrodes and a smaller sum of numbers of pairs of electrode fingers of the interdigital transducer electrodes, compared with the interdigital transducer electrodes connected to the first path on a first terminal side.

Abstract: A filter includes a series resonator or a longitudinally coupled resonator on a path connecting a first input-and-output terminal and a second input-and-output terminal, and parallel resonators each connected between the path and a ground. Among the parallel resonators, a second parallel resonator and a first parallel resonator are connected in parallel without another resonator being interposed therebetween. An IDT electrode of the first parallel resonator includes different electrode finger pitches. An average of all the electrode finger pitches of the IDT electrode of the first parallel resonator is larger than an average of all the electrode finger pitches of an IDT electrode of the second parallel resonator.

Abstract: A filter device includes a filter circuit including series-arm resonators and series-arm-resonator connecting wires, and an additional circuit including a resonator including first and second interdigital transducer electrodes, first and second capacitors connected between the first and second interdigital transducer electrodes and the filter circuit, and first and second I-C connecting wires connected to the first and second interdigital transducer electrodes and the first and second capacitors, the additional circuit being connected in parallel with a portion of the series-arm resonators in the filter circuit. The first and second interdigital transducer electrodes are output-side interdigital transducer electrodes. A capacitance of the first capacitor is smaller than the capacitance of the second capacitor.

Abstract: A multiplexer includes a common terminal, a first terminal, a second terminal, a first filter device including acoustic wave resonators including series resonators and parallel resonators, an inductor provided between an acoustic wave resonator and the first terminal, and a second filter device. The first filter device further includes a first ground terminal to which a parallel resonator is electrically connected, a second ground terminal to which the parallel resonators are electrically connected, and a wiring provided between the inductor and an acoustic wave resonator. In the first filter device, the wiring is electrically connected to the first ground terminal, and the first ground terminal is not connected to the second ground terminal.

Abstract: An acoustic wave filter device includes at least one series arm resonator and a parallel arm resonator. The series arm resonators and the parallel arm resonator are defined by acoustic wave resonators, an interdigital transducer electrode of the series arm resonators is an apodized interdigital transducer electrode subjected to apodization weighting, in the interdigital transducer electrode of the parallel arm resonator, an intersecting portion includes a central region and low acoustic velocity regions provided at both outer side portions of the central portion, an acoustic velocity of an acoustic wave in the low acoustic velocity region is lower than an acoustic velocity of an acoustic wave in the central region, and a high acoustic velocity region where an acoustic velocity of an acoustic wave is higher than that of the low acoustic velocity region is provided at an outer side portion of each of the low acoustic velocity regions.

Abstract: A filter device includes a filter circuit including first and second terminals and series arm resonators along a series arm connecting the first terminal and the second terminal, and an additional circuit connected in parallel at least some of the series arm resonators. The additional circuit includes first, second, and third interdigital transducer electrodes. The first interdigital transducer electrode is connected to a first node at one end portion of a series arm resonator having a lowest anti-resonant frequency of the series arm resonators, the second interdigital transducer electrode is connected to a second node having a potential different from a potential of the first node, the third interdigital transducer electrode is connected to a third node having a potential different from the potentials of the first and second nodes, and the first and second nodes are closer to the first terminal than the third node.

Abstract: A filter includes a ladder filter including a first parallel arm resonator and a second parallel arm resonator, a longitudinally coupled resonator filter electrically connected in series to the ladder filter, a first ground terminal electrically connected to the first parallel arm resonator, a second ground terminal electrically connected to the second parallel arm resonator, a third ground terminal electrically connected to the longitudinally coupled resonator filter, a third signal path electrically connected to a first node on a first signal path electrically connecting the second parallel arm resonator to the second ground terminal and a second node on a second signal path electrically connecting the longitudinally coupled resonator filter to the third ground terminal, and an inductor electrically connected between the first node on the first signal path and the second ground terminal or between the second node on the second signal path and the third ground terminal.

Abstract: A multiplexer includes first and second filters and additional circuits. The first filter is coupled to transmit and antenna terminals, the second filter is coupled to receive and antenna terminals, one additional circuit is coupled to transmit and receive terminals, and another additional circuit is coupled to transmit and antenna terminals. Pass bands of the first and second filters are respectively first and second frequency bands, and the second frequency band including a center frequency higher than a center frequency of the first frequency band. The one additional circuit includes a first resonator group including first IDT electrodes aligned in a propagation direction of an acoustic wave. The other additional circuit includes a second resonator group including second IDT electrodes aligned in the propagation direction. An average pitch of electrode fingers is greater among the first IDT electrodes than the second IDT electrodes.