An elastic wave device includes a low acoustic velocity film, a piezoelectric film, and an IDT electrode, which are laminated on a high acoustic velocity material. In the IDT electrode, first electrode fingers, or second electrode fingers, or each of the first electrode fingers and the second electrode fingers, includes a wide width portion with a dimension in a width direction larger than a dimension at a center in a length direction and being provided closer to at least one of a side of a proximal end and a side of a distal end than a central region, at least one of a first busbar and a second busbar includes cavities arranged in a busbar length direction, and at least one of the first busbar and the second busbar includes an inner busbar portion which is positioned closer to a side of the first electrode fingers or a side of the second electrode fingers than the cavities are and which extends in the length direction of the first busbar and the second busbar, a central busbar portion that includes the cavities, and an outer busbar portion.

An acoustic wave filter device includes a piezoelectric layer, a high-acoustic-velocity member, a low-acoustic-velocity film between the high-acoustic-velocity member and the piezoelectric layer, and first and second IDT electrodes on the piezoelectric layer to define acoustic wave resonators. An acoustic wave resonator of a series-arm resonator portion closest to an antenna end and/or an acoustic wave resonator of a parallel-arm resonator portion closest to the antenna end includes the first IDT electrode including first and second electrode fingers, and the remaining acoustic wave resonators include the second IDT electrode including third and fourth electrode fingers. In the first IDT electrode, a central area, first and second low-acoustic-velocity areas, and first and second high-acoustic-velocity areas extend along a direction perpendicular or substantially perpendicular to an acoustic wave propagating direction. First and second envelopes connecting the tips of the third and fourth electrode fingers of the second IDT electrode are inclined.

An acoustic wave resonator includes: a piezoelectric substrate; and an IDT that is located on the piezoelectric substrate and includes first regions and second regions alternately arranged in an extension direction of electrode fingers, which excite an acoustic wave, in an overlap region in which the electrode fingers overlap, at least one electrode finger of the electrode fingers in the second regions having a different width from the at least one electrode finger in the first regions, a width of an outer second region of the second regions in the extension direction differs from a width of an inner second region of the second regions.

A filter includes series resonators on a signal path, each of the series resonator including an IDT electrode that includes first electrode fingers each including a variant portion, second electrode fingers each including no variant portion, or both the first electrode fingers and the second electrode fingers, in the IDT electrode of one or more series resonators of the series resonators, a direction connecting other-side end portions of electrode fingers crosses an acoustic wave propagation direction, the IDT electrode includes the first electrode fingers, a first portion of an IDT electrode of another series resonator centrally located in the acoustic wave propagation direction, includes only the first electrode fingers, and a second portion and a third portion on two sides of the first portion each include only the second electrode fingers.

An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and reflectors. The interdigital transducer electrode includes first and second busbars including first and second cavities in a first direction, and first and second edge regions and first and second gap regions. The first and second edge regions include low acoustic velocity regions. Regions in which the first and second cavities are provided include high acoustic velocity regions. The reflector includes first and second reflector busbars and first reflection electrode fingers each including a second end portion that faces the second reflector busbar. The first reflection electrode fingers overlap the entire or substantially the entire second gap region when viewed in the first direction.

A filter includes series resonators in a signal path. An IDT electrode included in the series resonators includes at least either first electrode fingers including variant portions or second electrode fingers not including variant portions. In the IDT electrode included in one or more series resonators of the series resonators, a direction that connects the respective other ends of a plurality of electrode fingers intersects an acoustic wave propagation direction. In a first portion and a second portion of the IDT electrode, the first and second electrode fingers are arranged in a predetermined order.

Aspects of the disclosure relate to an electroacoustic device that includes a piezoelectric material and an electrode structure that includes a first busbar and a second busbar along with electrode fingers arranged in an interdigitated manner and including a first plurality of fingers connected to the first busbar and a second plurality of fingers connected to the second busbar. The electrode structure further includes a first conductive structure disposed between each of the first plurality of fingers and disposed between the first busbar and the second plurality of fingers. The electrode structure further includes a second conductive structure disposed between each of the second plurality of fingers and disposed between the second busbar and the first plurality of fingers. The first conductive structure and the second conductive structure each have a height that is less than a height of the second plurality of fingers.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a multi-layer mass loading strip. The mass loading strip has a density that is higher than a density of the temperature compensation layer. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can include a first layer for adhesion and a second layer for mass loading. The mass loading strip can suppress a transverse mode.

An acoustic wave device includes an acoustic wave resonator and a longitudinally coupled acoustic wave resonator filter, in which the longitudinally coupled acoustic wave resonator filter is shorter than the acoustic wave resonator in terms of a length of first and second edge regions that is a dimension along an extending direction of electrode fingers of the first and second edge regions in an IDT electrode.