Acoustic wave device

An acoustic wave device to be connected between a ground potential and a connection point between a first signal end and a second signal end of a filter device, the acoustic wave device comprising:

• a support;
• a piezoelectric layer on the support, the piezoelectric layer including an X-axis, a Y-axis, and a Z-axis that are crystal axes and being made of Z-cut lithium niobate;
• and
• an IDT electrode on the piezoelectric layer;
• wherein
• the IDT electrode includes a first busbar and a second busbar that face each other, a plurality of first electrode fingers each including one end connected to the first busbar, and a plurality of second electrode fingers each including one end connected to the second busbar and being interdigitated with the plurality of first electrode fingers;
• 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 of the first electrode fingers and the second electrode fingers adjacent to each other;
• the plurality of first electrode fingers and the plurality of second electrode fingers extend in a direction perpendicular or substantially perpendicular to a direction of the Y-axis of the piezoelectric layer, and a direction in which an envelope extends and the direction of the Y-axis intersect each other, the envelope being an imaginary line connecting tips of the plurality of first electrode fingers;
• and
• |α|<about 9° or about 14°<|α| is satisfied, where |α| is an absolute value of a slant angle α, the slant angle α being an angle of a corner that is defined by the direction in which the envelope extends and the direction of the Y-axis and being an angle other than 0°.