Abstract: A multiplexer includes a common terminal, first and second input/output terminals, a filter connected between the common terminal and the first input/output terminals and having a pass band including a first frequency band, a filter that is connected between the common terminal and the second input/output terminal and having a pass band including a second frequency band lower than the first frequency band, and an additional circuit including a first end connected to the common terminal and a second end connected to portion of a path connecting the common terminal and the first input/output terminal, the portion excluding the common terminal. The additional circuit includes a resonator including IDT electrodes on a piezoelectric substrate, and the IDT electrode with a widest electrode finger pitch is connected to the common terminal.

Abstract: An extractor includes an external connection terminal, a common terminal, input-output terminals, a band elimination filter that is connected to the common terminal and the first input-output terminal input-output terminal and that uses a first frequency band as a stop band, a band pass filter connected to the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band, and an inductor connected on a path connecting the common terminal to the external connection terminal. The band elimination filter includes series arm resonators located on a series arm connecting the common terminal to the input-output terminal and an inductor that is located on the series arm between the series arm resonator and the first input-output terminal. The inductor is inductively coupled to the inductor.

Abstract: A multiplexer includes a first filter connected between a common terminal and an input/output terminal and having a pass band including a first frequency band, a second filter connected between the common terminal and an input/output terminal and having a pass band including a second frequency band higher than the first frequency band, and an additional circuit connected in parallel to a path connecting the common terminal and the input/output terminal. The additional circuit includes a longitudinally coupled resonator including IDT electrodes. If a peak frequency in an IDT response occurring in a bandpass characteristic of the additional circuit is f1, and if a frequency corresponding to a lowest impedance among frequencies higher than the second frequency band in an impedance characteristic viewing the multiplexer from the common terminal is f2, f2×(1?0.0012)?f1?f2×(1+0.0012) is satisfied.

Abstract: An extractor includes an external connection terminal, a common terminal, input-output terminals, a band elimination filter that is connected to the common terminal and the first input-output terminal input-output terminal and that uses a first frequency band as a stop band, a band pass filter connected to the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band, and an inductor connected on a path connecting the common terminal to the external connection terminal. The band elimination filter includes series arm resonators located on a series arm connecting the common terminal to the input-output terminal and an inductor that is located on the series arm between the series arm resonator and the first input-output terminal. The inductor is inductively coupled to the inductor.

Abstract: A filter device includes a common connection terminal, a first bandpass filter connected to the common connection terminal and including an inductor, and a second bandpass filter connected to the common connection terminal and having a pass band lower in frequency than a pass band of the first bandpass filter. The filter device uses SH waves. The first bandpass filter is a ladder filter. Each of series arm resonators and parallel arm resonators includes an interdigital transducer electrode. Of the parallel arm resonators of the first bandpass filter, the inductor is connected in series to the parallel arm resonator with a shortest electrode finger pitch of the interdigital transducer electrode.

Abstract: An extractor includes a band elimination filter that is connected between a common terminal and a first input-output terminal and that has a stop band equal or substantially equal to a first frequency band, and a band pass filter that is connected between the common terminal and a second input-output terminal and that has a pass band equal or substantially equal to a second frequency band that overlaps the first frequency band. The band pass filter includes, series arm resonators, three or more parallel arm resonators, and three or more inductors that are connected between the ground and the parallel arm resonators. The L value of a first inductor that is connected and nearest to the common terminal is smaller than the L value of a third inductor, and the L value of a second inductor that is connected and second-nearest to the common terminal is smaller than the L value of the third inductor.

Abstract: A filter device includes a common connection terminal, a first bandpass filter connected to the common connection terminal and including an inductor, and a second bandpass filter connected to the common connection terminal and having a pass band lower in frequency than a pass band of the first bandpass filter. The filter device uses SH waves. The first bandpass filter is a ladder filter. Each of series arm resonators and parallel arm resonators includes an interdigital transducer electrode. Of the parallel arm resonators of the first bandpass filter, the inductor is connected in series to the parallel arm resonator with a shortest electrode finger pitch of the interdigital transducer electrode.

Abstract: An extractor includes an external connection terminal, a common terminal, input-output terminals, a band elimination filter that is connected to the common terminal and the first input-output terminal input-output terminal and that uses a first frequency band as a stop band, a band pass filter connected to the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band, and an inductor connected on a path connecting the common terminal to the external connection terminal. The band elimination filter includes series arm resonators located on a series arm connecting the common terminal to the input-output terminal and an inductor that is located on the series arm between the series arm resonator and the first input-output terminal. The inductor is inductively coupled to the inductor.

Abstract: An extractor includes a band pass filter and a band elimination filter. In the band pass filter, an IDT electrode in at least one of a first series arm resonator and a first parallel arm resonator that are arranged at a series arm and a parallel arm, respectively, closest to a common terminal is a first IDT electrode in which neither a plurality of first electrode fingers nor a plurality of second electrode fingers is partially missing, and an IDT electrode in at least one of the first series arm resonator or the first parallel arm resonator that does not include the first IDT electrode, second series arm resonators, and second parallel arm resonators is a second IDT electrode in which at least one of a plurality of electrode fingers and a plurality of second electrode fingers is partially missing.

Abstract: A ladder filter includes serial arm resonators disposed along a serial arm and parallel arm resonators disposed along corresponding parallel arms. Ladder circuit units are disposed along a path from an input terminal, which is a first end, to an output terminal, which is a second end. Each of the ladder circuit units includes a single serial arm resonator and a single parallel arm resonator. The ladder circuit units are mirror-connected to one another. The impedance at the first end is different from the impedance at the second end.

Abstract: An extractor includes a band elimination filter that is connected between a common terminal and a first input-output terminal and that has a stop band equal or substantially equal to a first frequency band, and a band pass filter that is connected between the common terminal and a second input-output terminal and that has a pass band equal or substantially equal to a second frequency band that overlaps the first frequency band. The band pass filter includes, series arm resonators, three or more parallel arm resonators, and three or more inductors that are connected between the ground and the parallel arm resonators. The L value of a first inductor that is connected and nearest to the common terminal is smaller than the L value of a third inductor, and the L value of a second inductor that is connected and second-nearest to the common terminal is smaller than the L value of the third inductor.

Abstract: An extractor includes a band pass filter and a band elimination filter. In the band pass filter, an IDT electrode in at least one of a first series arm resonator and a first parallel arm resonator that are arranged at a series arm and a parallel arm, respectively, closest to a common terminal is a first IDT electrode in which neither a plurality of first electrode fingers nor a plurality of second electrode fingers is partially missing, and an IDT electrode in at least one of the first series arm resonator or the first parallel arm resonator that does not include the first IDT electrode, second series arm resonators, and second parallel arm resonators is a second IDT electrode in which at least one of a plurality of electrode fingers and a plurality of second electrode fingers is partially missing.

Abstract: A ladder filter includes serial arm resonators disposed along a serial arm and parallel arm resonators disposed along corresponding parallel arms. Ladder circuit units are disposed along a path from an input terminal, which is a first end, to an output terminal, which is a second end. Each of the ladder circuit units includes a single serial arm resonator and a single parallel arm resonator. The ladder circuit units are mirror-connected to one another. The impedance at the first end is different from the impedance at the second end.

Abstract: A ladder-type surface acoustic wave filter includes interdigital transducer electrodes disposed on a LiTaO3 piezoelectric substrate, and series resonators and parallel resonators defined by the interdigital transducer electrodes, and utilizes a leaky wave that propagates on the LiTaO3 piezoelectric substrate. A bandwidth ratio indicating a bandwidth of a passband of the ladder-type surface acoustic wave filter is about 2.5% or greater, and a cutoff frequency due to bulk wave radiation of one of the parallel resonators, is in a frequency range higher than the passband.

Abstract: A filter apparatus includes a plurality of stages of ladder circuits connected between an input terminal and an output terminal, and a band width ratio is about 4.3 % or higher. The ladder circuits of respective stages include series arm resonators, parallel arm resonators, first inductors respectively connected between a ground potential and first end portions, and second inductors respectively connected between the ground potential and second end portions.

Abstract: A ladder-type surface acoustic wave filter includes interdigital transducer electrodes disposed on a LiTaO3 piezoelectric substrate, and series resonators and parallel resonators defined by the interdigital transducer electrodes, and utilizes a leaky wave that propagates on the LiTaO3 piezoelectric substrate. A bandwidth ratio indicating a bandwidth of a passband of the ladder-type surface acoustic wave filter is about 2.5% or greater, and a cutoff frequency due to bulk wave radiation of one of the parallel resonators, is in a frequency range higher than the passband.

Abstract: A filter apparatus includes a plurality of stages of ladder circuits connected between an input terminal and an output terminal, and a band width ratio is about 4.3% or higher. The ladder circuits of respective stages include series arm resonators, parallel arm resonators, first inductors respectively connected between a ground potential and first end portions, and second inductors respectively connected between the ground potential and second end portions.

Abstract: An inexpensive compact band rejection filter realizes a high sharpness of a filter characteristic at ends of passbands and has a large attenuation. In the band rejection filter, at least one of a plurality of elastic wave resonators, which contributes to formation of a transition band, has a propagation angle larger than those of the other elastic wave resonators. Accordingly, the at least one of the plurality of elastic wave resonators which contributes to the formation of the transition band has an electromechanical coupling coefficient that is smaller than electromechanical coupling coefficients of the other elastic wave resonators.

Abstract: A surface acoustic wave device includes an electrode and a dielectric layer laminated on a piezoelectric substrate, in which the electrode includes a first electrode film containing Pt, Au, Ag, or Cu and a second electrode film containing Al, the normalized film thickness h/? of the first electrode film is about 0.005 or more and at most about 0.015 in the case of Pt, the normalized film thickness h/? of the Al film is about 0.06 or more and at most about 0.185, and the normalized film thickness h/? of the dielectric layer is about 0.2 or less.

Abstract: A surface acoustic wave device includes an electrode and a dielectric layer laminated on a piezoelectric substrate, in which the electrode includes a first electrode film containing Pt, Au, Ag, or Cu and a second electrode film containing Al, the normalized film thickness h/? of the first electrode film is about 0.005 or more and at most about 0.015 in the case of Pt, the normalized film thickness h/? of the Al film is about 0.06 or more and at most about 0.185, and the normalized film thickness h/? of the dielectric layer is about 0.2 or less.