Acoustic wave device, high-frequency front end circuit, and communication device

An acoustic wave device, comprising:

• a piezoelectric body;
• and
• an IDT electrode provided on the piezoelectric body and including a main electrode layer;
• wherein
• the IDT electrode includes a first busbar and a second busbar facing each other, a plurality of first electrode fingers first ends of which are connected with the first busbar, and a plurality of second electrode fingers first ends of which are connected with the second busbar, the plurality of second electrode fingers being interdigitated with the plurality of first electrode fingers;
• the IDT electrode further includes an intersecting region in which the plurality of first electrode fingers and the plurality of second electrode fingers overlap each other in an acoustic wave propagation direction;
• when a direction in which the plurality of first electrode fingers extend or a direction in which the plurality of second electrode fingers extend is defined as a length direction, the intersecting region includes a central region located at a central portion of the first electrode fingers and the second electrode fingers in the length direction, a first low acoustic wave region which is disposed on an outside of the central region on a side of the first busbar in the length direction and in which an acoustic velocity is lower than an acoustic velocity in the central region, and a second low acoustic velocity region which is disposed on an outside of the central region on a side of the second busbar in the length direction and in which an acoustic velocity is lower than the acoustic velocity in the central region;
• a first high acoustic velocity region which is disposed on an outside of the first low acoustic velocity region on the side of the first busbar in the length direction and in which an acoustic velocity is higher than the acoustic velocity in the central region, and a second high acoustic velocity region which is disposed on an outside of the second low acoustic velocity region on the side of the second bulbar in the length direction and in which an acoustic velocity is higher than the acoustic velocity in the central region are provided;
• a duty ratio in the first low acoustic velocity region and the second low acoustic velocity region is greater than a duty ratio in the central region;
• an acoustic velocity ratio V3/V1 between the first high acoustic velocity region and the second high acoustic velocity region, and the central region is about 1.08;
• and
• the main electrode layer includes any one of Au, Pt, Ta, Cu, Ni, and Mo as a main component.