A multiplexer includes a transmission-side filter electrically connected to a common terminal and a transmission input terminal, and a transmission-side filter electrically connected to the common terminal and a transmission input terminal. The transmission-side filter includes a plurality of series arm resonators and a plurality of parallel arm resonators. Capacitance elements are respectively electrically connected in parallel to the series arm resonator and the parallel arm resonator, which are connected most proximately to the common terminal. IDT electrodes of a series arm resonator and a parallel arm resonator connected most proximately to the common terminal do not include a thinning electrode, and others of the series arm resonators and the parallel arm resonators include thinning electrodes.

An acoustic wave sensor device, comprising an interdigitated transducer; a first reflection structure arranged on one side of the interdigitated transducer, and a second reflection structure arranged on another side of the interdigitated transducer; a first resonance cavity comprising a first upper surface and formed between the interdigitated transducer and the first reflection structure; a second resonance cavity comprising a second upper surface and formed between the interdigitated transducer and the second reflection structure; and wherein the second upper surface comprises a physical and/or chemical modification as compared to the first upper surface.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

An acoustic wave device includes a piezoelectric film and an IDT electrode on the piezoelectric film. The IDT electrode includes first and second busbars, at least one first electrode finger, and at least one second electrode finger. When an overlap region is defined as a region in which the first and second electrode fingers overlap each other in an acoustic wave propagation direction, points A2, B2, C2, and D2, defined as follows, are all outside the cavity when, at the points A2, B2, C2, and D2, xa>about 25 μm, ya>about 25 μm, xb>about 25 μm, yb>about 25 μm, xc>about 25 μm, yc>about 25 μm, xd>about 25 μm, and yd>about 25 μm.

An apparatus is disclosed for a surface-acoustic-wave filter with an electrical conductor having a floating potential. In an example aspect, the apparatus includes a surface-acoustic-wave filter with a piezoelectric layer and an electrode structure disposed on a surface of the piezoelectric layer. The electrode structure includes a first comb-shaped structure and a second comb-shaped structure. The electrode structure also includes at least one electrical conductor positioned between the first comb-shaped structure and the second comb-shaped structure such that a gap separates the at least one electrical conductor from the first comb-shaped structure and the second comb-shaped structure.

An acoustic wave filter includes a divided resonator group and series arm resonators in a path connecting an input-output terminal and an input-output terminal to each other and parallel arm resonators each between a node in the path described above and the ground. The divided resonator group, the series arm resonators, and the parallel arm resonators each include an acoustic wave resonator including an interdigital transducer electrode on a piezoelectric substrate. The divided resonator group includes divided resonators coupled in series with each other. The IDT electrode included in the divided resonator includes a first withdrawal electrode. The IDT electrode included in the divided resonator includes a second withdrawal electrode different from the first withdrawal electrode with respect to the electrode finger structure.

A Lamb wave resonator includes a piezoelectric material layer, a first finger electrode, a second finger electrode, at least two floating electrodes, and at least two gaps. The first finger electrode is disposed on one side of the piezoelectric material layer and includes a first main portion and first fingers. The second finger electrode is disposed on the side of the piezoelectric material layer and includes a second main portion and second fingers. The first fingers are parallel to and alternately arranged with the second fingers. The floating electrodes are disposed between each first finger and each second finger, and the gaps are disposed at two ends of each floating electrode, respectively.

An acoustic wave sensor device comprises a quartz material layer comprising a planar surface, a first interdigitated transducer formed over the planar surface of the quartz material layer, a first reflection structure formed over the planar surface of the quartz material layer, a second reflection structure formed over the planar surface of the quartz material layer, a first resonance cavity formed between the first interdigitated transducer and the first reflection structure and a second resonance cavity formed between the first interdigitated transducer and the second reflection structure. The planar surface of the quartz material layer is defined by a crystal cut of a quartz material of the quartz material layer with angles φ in the range of −14° to −24°, θ in the range of −25° to −45° and ψ in the range of +8° to +28°.

An acoustic wave filter includes series arm resonators each including an IDT electrode on a piezoelectric substrate. Resonant frequencies of the series arm resonators are positioned within the pass band of the acoustic wave filter. The IDT electrode includes a pair of comb-shaped electrodes. Each of the comb-shaped electrodes includes electrode fingers and a busbar electrode. The electrode fingers extend in a direction intersecting a propagation direction of acoustic waves and are parallel with each other. One end of an electrode finger and one end of another electrode finger are connected with each other by the busbar electrode. The IDT electrode of the series arm resonator with the lowest anti-resonant frequency includes two or more withdrawal-weighted floating electrodes without any of the electrode fingers of one of the comb-shaped electrodes interposed therebetween.

An acoustic wave device includes a piezoelectric substrate, a first interdigital transducer (IDT) electrode, reflectors on both sides of the first IDT electrode in a propagation direction of an acoustic wave, and a second IDT electrode facing the first IDT electrode with a reflector interposed therebetween. The first and second IDT electrodes include first and second intersecting areas in which electrode fingers overlap in the propagation direction. The first and second intersecting areas overlap in the propagation direction. A third busbar of the second IDT electrode is coupled to a first busbar of the first IDT electrode. A fourth busbar of the second IDT electrode is coupled to a ground potential. A resonant frequency of the second IDT electrode is in a frequency band of an interference wave signal.