An acoustic wave device includes a piezoelectric substrate, and an IDT electrode on the piezoelectric substrate, and the IDT electrode includes an intersection region in which first and second electrode fingers overlap each other in an acoustic wave propagation direction, the intersection region includes a central region and first and second low acoustic velocity regions outside the central region on respective sides in an extending direction of the first and second electrode fingers, first and second busbars include first and second cavities, respectively, first and second inner busbar portions on one side of the first and second cavities, and first and second outer busbar portions on another side are connected by first and second connecting portions, and at least one of the first connecting portions and at least one of the second connecting portions are a first wide width connecting portion and a second wide width connecting portion having a width wider than that of each of remaining first and second connecting portions.

An acoustic wave device includes a plurality of interdigital transducer electrodes, in a first interdigital transducer electrode, a first electrode finger includes a wide portion having a greater width in the second direction than a center portion. In the first interdigital transducer electrode, for the first electrode finger, a first distance that is a maximum distance in the second direction between a center line of the center portion in a first direction is shorter than a second distance that is a maximum distance in a second direction between the center line of the center portion and an outer edge, away from a second interdigital transducer electrode, of the wide portion.

An acoustic wave resonator includes: a piezoelectric substrate; and a pair of grating electrodes that is formed on the piezoelectric substrate, one of the pair of grating electrodes including a plurality of first electrode fingers having electric potentials equal to each other, another of the pair of grating electrodes including a plurality of second electrode fingers having electric potentials that differ from the electric potentials of the plurality of first electrode fingers and are equal to each other, two second electrode fingers of the plurality of second electrode fingers being located between at least a pair of adjacent first electrode fingers of the plurality of first electrode fingers, Pg differing from λ/4 where λ represents a wavelength of an acoustic wave excited by the plurality of first electrode fingers and the plurality of second electrode fingers and Pg represents a distance between centers of the two second electrode fingers.

An acoustic wave device includes a piezoelectric body portion, an interdigital transducer electrode connected to a first terminal and a second terminal, and a reflector connected to the second terminal. In the interdigital transducer electrode, in the interdigital transducer electrode, where, of a group of electrode fingers, the electrode finger located at one end in a second direction is a first end electrode finger and the electrode finger located at another end is a second end electrode finger, the first end electrode finger is located between the reflector and the second end electrode finger in the second direction. An outer busbar portion of one of a first busbar and a second busbar, not connected to the first end electrode finger, is located on an inner side in the second direction relative to a center portion, in a first direction, of the first end electrode finger.

An elastic wave resonator including a piezoelectric substrate and an IDT electrode, the IDT electrode includes a first electrode finger and a second electrode finger arranged next to the first electrode finger; when W.sub.1 is the width of the first electrode finger, W.sub.2 is the width of the second electrode finger, and L is a pitch or an electrode finger center distance between the first electrode finger and the second electrode finger; a metallization ratio (W.sub.1/L) of the first electrode finger is smaller than a metallization ratio (W.sub.2/L) of the second electrode finger; a sum (W.sub.1/L+W.sub.2/L) of the metallization ratio of the first electrode finger and the metallization ratio of the second electrode finger is between about 0.65 and about 1.00 inclusive, and a ratio (W.sub.2/W.sub.1) between a width of the first electrode finger and a width of the second electrode finger is between about 1.12 and about 2.33 inclusive, or W.sub.1/L+W.sub.2/L is larger than about 1.00, and W.sub.2/W.sub.1 is between about 1.40 and about 2.34 inclusive.

A capacitive element includes a piezoelectric substrate, a first electrode finger extending towards a positive side in a first direction, and a second electrode finger disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger. The first electrode finger includes a first portion extending in the first direction and a second portion extending from the first portion, through a first step portion, and at a different position in the second direction from the first portion. The second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion through a second step portion, extending from the second portion in the first direction, and facing the first portion.

A surface acoustic wave device includes a piezoelectric substrate and a pair of interdigital transducer electrodes. The pair of interdigital transducer electrodes include an alternating region as a region where the electrode fingers connected to one busbar and the electrode fingers connected to the other busbar are alternately provided. When a region on an end portion side of the alternating region and a region including distal end portions of the plurality of electrode fingers is referred to as an edge region, a propagation velocity of a surface acoustic wave in the edge region is slower than a propagation velocity of a surface acoustic wave in the alternating region. A propagation velocity of a surface acoustic wave in a busbar region as a region where the busbar is disposed is faster than the propagation velocity of the surface acoustic wave in the alternating region.

An acoustic wave device comprises a substrate including a piezoelectric material, and interdigital transducer (IDT) electrodes disposed on a surface of the substrate. The IDT electrodes have gap regions, edge regions, and center regions. A maximum width of the IDT electrodes in the gap regions is greater than the maximum width of the IDT electrodes in the edge regions, thereby achieving a velocity of an acoustic wave in the gap regions being greater than the velocity of the acoustic wave in the center regions, and the velocity of the acoustic wave in the center regions being greater than the velocity of the acoustic wave in the edge regions.

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.

Disclosed is a surface acoustic wave device including a piezoelectric substrate, first and second bus bars formed on the piezoelectric substrate to be opposite each other, a plurality of first inter-digital electrodes that are electrically connected to the first bus bar and extend from the first bus bar toward the second bus bar, and a plurality of second inter-digital electrodes that are electrically connected to the second bus bar and extend from the second bus bar toward the first bus bar, in which the first inter-digital electrodes and the second inter-digital electrodes are alternately arranged.