Surface acoustic wave filter, surface acoustic wave device and communication device
AssigneeMurata Manufacturing Co., Ltd.
InventorKenichi Noto
Life of this patent
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Abstract
A longitudinally coupled resonator type surface acoustic filter includes a rotated Y-cut X-propagating LiTaO3 substrate. The gap length G in the IDT electrode of the surface acoustic wave resonator is about 0.3 times the wavelength λ of the surface acoustic wave or less. The gap length G is the spacing between the bus bars tips of the electrode fingers extending from one bus bar (electrode terminal) toward the other opposing bus bar of the IDT electrode included in the surface acoustic wave filter.
Claims15
A longitudinally coupled resonator type surface acoustic wave filter, comprising:
- a surface acoustic wave resonator including:
- a piezoelectric substrate;
- a plurality of interdigital transducer electrodes disposed adjacent to each other on the piezoelectric substrate along the propagating direction of a surface acoustic wave, each interdigital transducer electrode including a pair of electrode terminals that are opposite to each other and a plurality of electrode fingers that extend from each electrode terminal toward the opposite electrode terminal to define an interdigitated configuration;
- and
- reflecting members provided at two opposing ends of the plurality of interdigital transducer electrodes;
- wherein the piezoelectric substrate is made of a rotated Y-cut X-propagating LiTaO3, and the gap length between the tips of the electrode fingers that extend from one of the electrode terminals and the other opposite electrode terminal is less than or equal to about 0.3λ, where λ is the wavelength of the surface acoustic wave.
A longitudinally coupled resonator type surface acoustic wave filter, comprising:
- at least one surface acoustic wave resonator each including:
- a rotated Y-cut X-propagating LiTaO3 piezoelectric substrate;
- a plurality of interdigital transducer electrodes disposed adjacent to each other on the piezoelectric substrate along the propagating direction of a surface acoustic wave, each interdigital transducer electrode including a pair of electrode terminals that are opposite to each other and a plurality of electrode fingers that extend from each electrode terminal toward the opposite electrode terminal to define an interdigitated configuration;
- wherein the gap length between the tips of the electrode fingers that extend from one of the electrode terminals and the other opposite electrode terminal is less than or equal to about 0.3λ, where λ is the wavelength of the surface acoustic wave.
Dependencies are inferred from the claim text.