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 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 /4 where 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.

A surface acoustic wave (SAW) device includes: a substrate, an interdigitated transducer including a plurality of interdigitated fingers disposed on a first surface of the substrate, and a reflector including a plurality of gratings also disposed on the first surface. At least one of: (1) a first group of the interdigitated fingers has a first finger pitch and a first finger metal pitch ratio, and a second group of the interdigitated fingers has a second finger pitch different from the first metal pitch and a second metal pitch ratio different from the first metal pitch ratio; and (2) a first group of the gratings has a first grating pitch and a first grating metal pitch ratio, and a second group of the gratings has a second grating metal pitch different from the first grating metal pitch and a second grating metal pitch ratio different from the first grating metal pitch ratio.