Abstract: 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.

Abstract: An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, and an IDT electrode on the piezoelectric layer and including busbars and electrode fingers. In plan view when viewed in a lamination direction of the support and the piezoelectric layer, an acoustic reflector overlaps at least a portion of the IDT electrode on the support. When a thickness of the piezoelectric layer is defined as d and a center-to-center distance between the electrode fingers adjacent to each other is defined as p, d/p is about 0.5 or smaller. Mass addition films are located over at least one of pair of edge regions and a gap region adjacent to the edge region and aligned in an electrode finger facing direction. The mass addition films are not located on at least a portion between the adjacent electrode fingers.

Abstract: An acoustic wave device includes a piezoelectric substrate including a support that includes a support substrate, and a piezoelectric layer located on the support, a functional electrode located on the piezoelectric layer and including at least one pair of electrode fingers, and a dielectric film located on the piezoelectric layer to cover the at least one pair of electrode fingers. An acoustic reflection portion is located at a position overlapping at least a portion of the functional electrode in plan view. Assuming a thickness of the piezoelectric layer is d and a center-to-center distance between the electrode fingers adjacent to each other is p, d/p is about 0.5 or less. Angles of corners ?1, ?2, ?3, and ?4 are such that at least one of ?1??3 or ?2??4 is satisfied.

Abstract: An acoustic wave device includes a piezoelectric substrate including a support that includes a support substrate, and a piezoelectric layer on the support, a functional electrode on the piezoelectric layer and including a pair of electrode fingers, and a dielectric film covering the pair of electrode fingers. An acoustic reflection portion overlaps at least a portion of the functional electrode in plan view seen along a laminating direction of the support and the piezoelectric layer. Assuming a thickness of the piezoelectric layer is d and a center-to-center distance between adjacent electrode fingers is p, d/p is about 0.5 or less. A dielectric film ridge portion and an electrode finger ridge portion have a curved shape, in which a curvature radius of at least a portion of the dielectric film ridge portion is larger than a curvature radius of at least a portion of the electrode finger ridge portion.

Abstract: An acoustic wave device includes a piezoelectric substrate including a support including a support substrate and a piezoelectric layer on the support and made of lithium tantalate or lithium niobate, and an IDT electrode on the piezoelectric layer and including busbars and electrode fingers. d/p is less than or equal to about 0.5. Some electrode fingers are connected to one busbar. Remaining electrode fingers are connected to another busbar. A crossing region includes a central region and edge regions in an electrode-finger-extending direction. A non-support portion of the support overlaps the central region and about 90% or more of a portion of the edge regions located between the electrode fingers. A through-hole is provided in about 50% or more of the piezoelectric layer overlapping gap regions and located between the electrode fingers. The support portion overlaps a portion of the gap regions where the electrode fingers are provided.

Abstract: An acoustic wave device includes an energy confinement layer, a piezoelectric layer made of Y-cut X-propagation lithium tantalate having a cut angle in a range from about ?10° to about 65°, and an IDT electrode. Electrode fingers of the IDT electrode include an Al metal layer and a high acoustic impedance metal layer having a Young's modulus equal to or more than about 200 GPa and an acoustic impedance higher than Al. The high acoustic impedance metal layer is closer to the piezoelectric layer than the Al metal layer. A wavelength specific film thickness tLT of the piezoelectric layer is expressed by tLT?1?. The total of normalized film thicknesses obtained by normalizing the film thickness of each layer of the electrode finger by a density and Young's modulus of the Al metal layer satisfies T?0.1125tLT+0.0574.

Abstract: An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, and an IDT electrode including busbars and electrode fingers, and a mass-adding film on the piezoelectric layer. In plan view as seen in a stacking direction in which the support and the piezoelectric layer are stacked, an acoustic reflector overlaps at least a portion of the IDT electrode. d/p is less than or equal to about 0.5, where d is a thickness of the piezoelectric layer and p is a center-to-center distance between adjacent electrode fingers. A region in which adjacent electrode fingers overlap each other when seen from an electrode-finger-facing direction is a crossing region. Regions between the crossing region and the pair of busbars include first and second gap regions. The mass-adding film overlaps the gap region in plan view and is on the second main surface of the piezoelectric layer.

Abstract: An acoustic wave device includes a support substrate and first and second resonant sections adjacent to each other on the support substrate. Each of the first and second resonant sections includes a piezoelectric thin film, an IDT electrode on the piezoelectric thin film, and a support layer surrounding the piezoelectric thin film in a plan view of the acoustic wave device. The support layer has a different linear expansion coefficient from the piezoelectric thin film. The piezoelectric thin film in the first resonant section and the piezoelectric thin film in the second resonant section are divided by the support layer between the resonant section and the resonant section.

Abstract: An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, made of lithium niobate or lithium tantalate, and including a first main surface and a second main surface that oppose each other, and an interdigital transducer electrode on the first main surface of the piezoelectric layer. An acoustic reflection portion is at a position overlapping at least a portion of the IDT electrode in a plan view when viewed along a laminating direction of the support and the piezoelectric layer. The IDT electrode includes a first busbar and a second busbar that oppose each other, first electrode fingers each including one end connected to the first busbar, and second electrode fingers each including one end connected to the second busbar and being interdigitated with the plurality of first electrode fingers.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer on the support substrate, and an IDT electrode on the piezoelectric layer and including electrode fingers. Lithium niobate or lithium tantalate is used as a material of the piezoelectric layer. One of YAG, rutile, lanthanum aluminate, strontium titanate, or yttrium aluminate is used as a material of the support substrate.

Abstract: A first filter of a multiplexer includes serial resonators and parallel resonators that are acoustic wave resonators. A first of the serial resonators that is closer to a common terminal than the other serial resonators is connected to the common terminal without the parallel resonators interposed therebetween. Each of the elastic wave resonators includes a substrate having piezoelectricity, an IDT electrode provided on the substrate, and a dielectric layer provided on the substrate to cover the IDT electrode. A thickness of the dielectric layer of the first serial resonator is smaller than a thickness of each of the dielectric layers of the remainder of the elastic wave resonators.

Abstract: An acoustic wave device includes a support, a piezoelectric layer including lithium niobate or lithium tantalate, and an interdigital transducer electrode including busbars and electrode fingers. An acoustic reflection portion overlaps a portion of the IDT electrode. d/p is about 0.5 or less. An intersecting region includes a central region and edge regions. Gap regions are located between the intersecting region and the busbars. At least one mass addition film is provided in at least one of the edge regions or the gap regions, where any two points, in an electrode finger facing direction, of a portion in which the mass addition film is located are first and second points, thicknesses of the mass addition film at at least a pair of the first point and the second point are different from each other.

Abstract: An acoustic wave device includes a piezoelectric substrate, and an IDT electrode on the piezoelectric substrate. The piezoelectric substrate includes a high acoustic velocity layer, and a piezoelectric layer. The IDT electrode includes a first busbar and a second busbar, and first and second electrode fingers interdigitated with each other. A first envelope and a second envelope each extend in a slanted direction with respect to an acoustic wave propagation direction, the first envelope being an imaginary line formed by connecting tips of the first electrode fingers, the second envelope being an imaginary line formed by connecting tips of the second electrode fingers. The first dielectric film is located in at least one gap of first and second gaps, the first gaps being located between the first electrode fingers and the second busbar, the second gaps being located between the second electrode fingers and the first busbar. The first dielectric film has a density greater than a density of silicon oxide.

Abstract: An acoustic wave device includes a piezoelectric body including first and second main surfaces facing each other, an IDT electrode provided on the first main surface of the piezoelectric body and including electrode fingers, a high acoustic velocity member on the second main surface side of the piezoelectric body, in which an acoustic velocity of a propagating bulk wave is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric body, and a first dielectric film provided on an upper surface of the electrode fingers, in which a portion where a dielectric is not present is provided between the electrode fingers of the IDT electrode.

Abstract: An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support and including a lithium niobate layer or a lithium tantalate layer, and an IDT electrode on the piezoelectric layer and including a pair of busbars and electrode fingers. The support includes an acoustic reflector portion overlapping at least a portion of the IDT electrode in plan view. When a thickness of the piezoelectric layer is defined as d and a center-to-center distance between the electrode fingers adjacent to each other is defined as p, d/p is equal to or less than about 0.5. A region located between an intersection region and the pair of busbars is a pair of gap regions. An addition film having a higher dielectric constant and density than silicon oxide is provided in at least one of the pair of gap regions.

Abstract: An acoustic wave device includes a support, a piezoelectric layer on the support, and an IDT electrode on the piezoelectric layer and includes a pair of busbars and electrode fingers. The support includes an acoustic reflection portion overlapping at least a portion of the IDT electrode. d/p is about 0.5 or less. Some of the electrode fingers are connected to one of the busbars, others of the electrode fingers are connected to another of the busbars. When viewed from a direction in which adjacent electrode fingers face each other, a region where the adjacent electrode fingers overlap each other is an intersection region. A region between the intersection region and the pair of busbars includes a pair of gap regions. A mass addition film is provided in at least a portion of at least one of the gap regions.

Abstract: An acoustic wave device includes an IDT electrode on a piezoelectric body and the IDT electrode includes first and second busbars, and first and second electrode fingers. A first dielectric film extends from a region between tip end portions of the first electrode fingers and the piezoelectric body to a region between the second busbar and the piezoelectric body with a first gap in between. The second electrode fingers are in direct contact with the piezoelectric body at a center of an overlap width, and a permittivity of the first dielectric film is lower than a permittivity of the piezoelectric body.

Abstract: In an acoustic wave device, an IDT electrode is located on a piezoelectric layer. A high-acoustic-velocity member is positioned on an opposite side of the piezoelectric layer from the IDT electrode. An acoustic velocity of a bulk wave propagating through the high-acoustic-velocity member is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer. A low-acoustic-velocity film is provided between the high-acoustic-velocity member and the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the low-acoustic-velocity film is lower than the acoustic velocity of the bulk wave propagating through the piezoelectric layer. A dielectric film is located on the piezoelectric layer so as to cover the IDT electrode. In the acoustic wave device, a Young's modulus of the dielectric film is larger than a Young's modulus of the low-acoustic-velocity film.

Abstract: An acoustic wave device includes a support substrate, an intermediate layer on the support substrate, a piezoelectric layer on the intermediate layer, a bonding layer between the support substrate and the piezoelectric layer, a low-resistivity layer between the support substrate and the piezoelectric layer, and an IDT electrode on the piezoelectric layer and including a pair of busbars and first and second electrode fingers. The low-resistivity layer closer to the piezoelectric layer than the bonding layer and includes Al as a main component.

Abstract: A surface acoustic wave element includes a substrate including a LiNbO3 piezoelectric single crystal, a first dielectric layer provided on the substrate, and an IDT electrode provided on the first dielectric layer, and propagates a high-frequency signal on the substrate using a Rayleigh wave.