Acoustic wave resonator, filter, and multiplexer

An acoustic wave resonator comprising:

• a piezoelectric substrate;
• and
• an IDT that is located on the piezoelectric substrate and includes a pair of comb-shaped electrodes facing each other, each of the pair of comb-shaped electrodes having grating electrodes, which excite an acoustic wave, and a bus bar connected to the grating electrodes, a duty ratio of grating electrodes of the pair of comb-shaped electrodes in a center region of an overlap region differing from a duty ratio of grating electrodes of the pair of comb-shaped electrodes in an edge region of the overlap region in at least a part of a region of the IDT in a direction in which the grating electrodes are arranged, the grating electrodes of each of the pair of comb-shaped electrodes overlapping with the grating electrodes of the other in the overlap region, a width of a grating electrode of a first comb-shaped electrode of the pair of comb-shaped electrodes in the center region differing from a width of a grating electrode of a second comb-shaped electrode of the pair of comb-shaped electrodes in the center region,
• wherein
• the grating electrode of the first comb-shaped electrode in the center region is wider than the grating electrode of the second comb-shaped electrode in the center region,
• a grating electrode of the first comb-shaped electrode in the edge region is narrower than a grating electrode of the second comb-shaped electrode in the edge region,
• the grating electrode of the first comb-shaped electrode in the edge region is narrower than the grating electrode of the first comb-shaped electrode in the center region, and
• the grating electrode of the second comb-shaped electrode in the edge region is wider than the grating electrode of the second comb-shaped electrode in the center region.

An acoustic wave resonator comprising:

• a piezoelectric substrate;
• and
• an IDT that Is located on the piezoelectric substrate and includes a pair of comb-shaped electrodes facing each other, each of the pair of comb-shaped electrodes having grating electrodes, which excite an acoustic wave, and a bus bar connected to the grating electrodes, a duty ratio of grating electrodes of the pair of comb-shaped electrodes in a center region of an overlap region differing from a duty ratio of grating electrodes of the pair of comb-shaped electrodes in an edge region of the overlap region in at least a part on a region of the IDT in a direction in which the grating electrodes are arranged, the grating electrodes of each of the pair of comb-shaped electrodes overlapping with the grating electrodes of the other in the overlap region, a width of a grating electrode of a first comb-shaped electrode of the pair of comb-shaped electrodes in the center region differing from a width of a grating electrode of a second comb-shaped electrode of the pair of comb-shaped electrodes in the center region,
• wherein
• the duty ratio of the grating electrodes of the pair of comb-shaped electrodes in the center region is greater than the duty ratio of the grating electrodes of the pair of comb-shaped electrodes in the edge region.