Abstract: A multiplexer includes a common terminal, an inductor including a first end connected to the common terminal and a second end, a filter connected to the second end and having a first pass band, a filter connected to the common terminal and having a second pass band located on a higher frequency side relative to the first pass band, an inductor connected between a ground and a path that links the second end to the filter, and a capacitor connected between the path and the ground. A resonant frequency of an LC parallel resonance circuit including the inductor and the capacitor is located between the first pass band and the second pass band.

Abstract: An acoustic wave filter device includes first and second acoustic wave filters provided on a piezoelectric substrate, an insulating layer that is provided on the piezoelectric substrate and has a smaller dielectric constant than the piezoelectric substrate, a first wiring conductor electrically connected to an electrode of the first acoustic wave filter, a second wiring conductor electrically connected to an electrode of the second acoustic wave filter, the first wiring conductor and the second wiring conductor facing each other on the insulating layer in plan view, and a ground conductor located between the insulating layer and the piezoelectric substrate in a region A circumscribing the first wiring conductor and the second wiring conductor on the insulating layer in plan view.

Abstract: A longitudinally coupled resonator acoustic wave filter includes a piezoelectric substrate, IDT electrodes on the piezoelectric substrate along an acoustic wave propagation direction, and a pair of reflectors on the piezoelectric substrate on both sides of the IDT electrodes in the acoustic wave propagation direction. Each of the reflectors includes first and second reflector busbars, and first reflective electrode fingers connected to at least one of the first reflector busbar and the second reflector busbar. The reflector includes a first portion in which lengths of the first reflective electrode fingers change in the acoustic wave propagation direction.

Abstract: An acoustic wave device includes a common terminal, a first terminal, a second terminal, a first filter, a second filter, and an inductor. The first filter has a pass band corresponding to a relatively low frequency range and includes a surface acoustic wave filter using an SH wave. The second filter has a pass band corresponding to a relatively high frequency range. The first filter is between a branch point and the first terminal on a path connecting the common terminal and the first terminal. The second filter is between the branch point and the second terminal on a path connecting the common terminal and the second terminal. The inductor is on a path connecting the branch point and the first filter.

Abstract: A surface acoustic wave filter includes a longitudinally coupled filter connected between an input terminal and an output terminal on a main surface of a piezoelectric substrate and that includes longitudinally coupled resonators and a parallel arm resonator connected between a node between the input terminal and the longitudinally coupled filter and ground. A line connecting IDT electrodes at an input side of a portion of the longitudinally coupled resonators to the ground and a line connecting the parallel arm resonator to the ground are independently provided and are connected to the same ground terminal.

Abstract: An elastic wave filter device includes first and second reception filters, an input terminal, output terminals, and reference terminals provided on a piezoelectric substrate. The first reception filter includes series resonators and parallel resonators, and the second reception filter includes series resonators and parallel resonators. The reference terminal connected to the parallel resonator connected so as to be closest to the output terminal among the parallel resonators included in the first reception filter, and the reference terminal connected to the parallel resonator connected so as to be closest to the output terminal among the parallel resonators included in the second reception filter, are separated from each other on the piezoelectric substrate.

Abstract: An acoustic wave device includes a common terminal, a first terminal, a second terminal, a first filter, a second filter, and an inductor. The first filter has a pass band corresponding to a relatively low frequency range and includes a surface acoustic wave filter using an SH wave. The second filter has a pass band corresponding to a relatively high frequency range. The first filter is between a branch point and the first terminal on a path connecting the common terminal and the first terminal. The second filter is between the branch point and the second terminal on a path connecting the common terminal and the second terminal. The inductor is on a path connecting the branch point and the first filter.

Abstract: An acoustic wave filter device includes first and second acoustic wave filters provided on a piezoelectric substrate, an insulating layer that is provided on the piezoelectric substrate and has a smaller dielectric constant than the piezoelectric substrate, a first wiring conductor electrically connected to an electrode of the first acoustic wave filter, a second wiring conductor electrically connected to an electrode of the second acoustic wave filter, the first wiring conductor and the second wiring conductor facing each other on the insulating layer in plan view, and a ground conductor located between the insulating layer and the piezoelectric substrate in a region A circumscribing the first wiring conductor and the second wiring conductor on the insulating layer in plan view.

Abstract: An elastic wave filter device includes first and second reception filters, an input terminal, output terminals, and reference terminals provided on a piezoelectric substrate. The first reception filter includes series resonators and parallel resonators, and the second reception filter includes series resonators and parallel resonators. The reference terminal connected to the parallel resonator connected so as to be closest to the output terminal among the parallel resonators included in the first reception filter, and the reference terminal connected to the parallel resonator connected so as to be closest to the output terminal among the parallel resonators included in the second reception filter, are separated from each other on the piezoelectric substrate.

Abstract: A surface acoustic wave filter includes a longitudinally coupled filter connected between an input terminal and an output terminal on a main surface of a piezoelectric substrate and that includes longitudinally coupled resonators and a parallel arm resonator connected between a node between the input terminal and the longitudinally coupled filter and ground. A line connecting IDT electrodes at an input side of a portion of the longitudinally coupled resonators to the ground and a line connecting the parallel arm resonator to the ground are independently provided and are connected to the same ground terminal.