Acoustic wave device

An acoustic wave device comprising:

• a piezoelectric layer;
• an interdigital transducer electrode on the piezoelectric layer;
• a pair of reflectors on the piezoelectric layer on both sides of the interdigital transducer electrode in a first direction in which an acoustic wave propagates, and a second direction is perpendicular or substantially perpendicular to the first direction;
• wherein
• the interdigital transducer electrode includes a first busbar and a second busbar that face each other and that include cavities in the first direction, first electrode fingers each including one end portion connected to the first busbar, and second electrode fingers each including one end portion connected to the second busbar, the second electrode fingers being interdigitated with the first electrode fingers;
• an intersection region is defined as a region in which the first electrode fingers and the second electrode fingers overlap in the first direction, and the intersection region includes a central region at a center in the second direction, a first edge region between the central region and the first busbar, and a second edge region between the central region and the second busbar;
• the interdigital transducer electrode includes a first gap region between the first edge region and the first busbar, and a second gap region between the second edge region and the second busbar;
• the first edge region and the second edge region include respective low acoustic velocity regions in which an acoustic velocity is lower than that in the central region, and regions in which the cavities of the first busbar and the second busbar are provided include respective high acoustic velocity regions in which an acoustic velocity is higher than that in the central region;
• each of the reflectors includes a first reflector busbar in a vicinity of the first busbar of the interdigital transducer electrode, a second reflector busbar facing the first reflector busbar and in a vicinity of the second busbar, and a first reflection electrode finger including one end portion connected to the first reflector busbar and another end portion facing the second reflector busbar with a gap interposed therebetween;
• and
• the first reflection electrode finger overlaps an entirety of substantially an entirety of the second gap region of the interdigital transducer electrode when viewed in the first direction.