Acoustic wave device

An acoustic wave device comprising:

• a piezoelectric substrate including a piezoelectric layer;
• a first interdigital transducer (IDT) electrode on the piezoelectric layer;
• a second IDT electrode on the piezoelectric layer;
• a first reflector and a second reflector on the piezoelectric layer and opposed to each other with the first IDT electrode interposed therebetween, and each including a plurality of reflector electrode fingers;
• and
• a third reflector and a fourth reflector on the piezoelectric layer and opposed to each other with the second IDT electrode interposed therebetween, and each including a plurality of reflector electrode fingers;
• wherein
• of the first reflector and the second reflector, the second reflector is located on a second IDT electrode side, and, of the third reflector and the fourth reflector, the third reflector is located on a first IDT electrode side;
• when a direction orthogonal or substantially orthogonal to a direction in which the plurality of reflector electrode fingers in the second reflector extend is defined as an orthogonal direction, the plurality of reflector electrode fingers in the second reflector and the plurality of reflector electrode fingers in the third reflector overlap each other in the orthogonal direction;
• when M is defined as a median of all of center-to-center distances between the reflector electrode fingers adjacent to each other as a plurality of pairs of the reflector electrode fingers in each of the second reflector and the third reflector, a mean value of the center-to-center distances within a range of M±about 40% is defined as a mean center-to-center distance, and λa<λb, where λa is a wavelength defined by the mean center-to-center distance in the second reflector and λb is a wavelength defined by the mean center-to-center distance in the third reflector;
• and
• a distance between the second reflector and the third reflector is a distance Xn within a range represented by the Formula 1, where n is any natural number:
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• 4
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• Xn
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• 4
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• .
• Formula
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• 1