Filter device
AssigneeMurata Manufacturing Co., Ltd.
InventorTetsuya Kimura
Life of this patent
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Abstract
A filter device includes first and second acoustic wave resonators each including a support, a piezoelectric layer that has an X-axis, a Y-axis, and a Z-axis that are crystal axes and is made of Y-cut lithium niobate, and an IDT electrode including first and second electrode fingers. When a thickness of the piezoelectric layer is d and a center-to-center distance of the first and second electrode fingers and the second electrode fingers adjacent to each other is p, d/p is less than or equal to 0.5. An absolute value of a first slant angle α1 differs from an absolute value of a second slant angle α2.
Claims20
A filter device comprising:
- a first acoustic wave resonator;
- and
- a second acoustic wave resonator;
- wherein
- each of the first acoustic wave resonator and the second acoustic wave resonator includes a support, a piezoelectric layer on the support, X-axis, a Y-axis, and a Z-axis that are crystal axes, is made of Y-cut lithium niobate, and includes an IDT electrode on the piezoelectric layer;
- the IDT electrode of each of the first acoustic wave resonator and the second acoustic wave resonator 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;
- in each of the first acoustic wave resonator and the second acoustic wave resonator, 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;
- when an imaginary line connecting tips of the plurality of first electrode fingers is an envelope in each of the first acoustic wave resonator and the second acoustic wave resonator, a direction in which the envelope extends and a direction of the X-axis intersect each other;
- and
- an absolute value of a first slant angle β1 and an absolute value of a second slant angle α2 differ from each other, the first slant angle β1 being an angle of a corner defined by the direction in which the envelope extends and the direction of the X-axis and being an angle other than 0° in the first acoustic wave resonator, and the second slant angle β2 being an angle of a corner defined by the direction in which the envelope extends and the direction of the X-axis and being an angle other than 0° in the second acoustic wave resonator.
Dependencies are inferred from the claim text.