Surface acoustic wave filter with a passband formed by a longitudinally coupled filter and a resonator inductance
AssigneeMurata Manufacturing Co., Ltd.
InventorYuichi Takamine
Life of this patent
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Abstract
A surface acoustic wave filter includes a longitudinally-coupled resonator-type surface acoustic wave filter having at least two interdigital transducers disposed on a piezoelectric substrate along the propagation direction of a surface acoustic wave, and at least one surface acoustic wave resonator connected between an input terminal and/or an output terminal and the longitudinally-coupled resonator-type surface acoustic wave filter. In this surface acoustic wave filter, a pass band is formed by utilizing at least one of the resonant modes of the longitudinally-coupled resonator-type surface acoustic wave filter and the inductance of the surface acoustic wave resonator.
Claims22
A surface acoustic wave filter, comprising:
- a longitudinally-coupled resonator-type surface acoustic wave filter having a piezoelectric substrate and at least two interdigital transducers disposed on the piezoelectric substrate along the propagation direction of a surface acoustic wave generated therein;
- and
- at least one surface acoustic wave resonator connected between at least one of an input terminal and an output terminal of the surface acoustic wave filter, and said longitudinally-coupled resonator-type surface acoustic wave filter;
- wherein a pass band is generated by utilizing at least one of the resonant modes of said longitudinally-coupled resonator-type surface acoustic wave filter and inductance of said at least one surface acoustic wave resonator.
A surface acoustic wave filter, comprising:
- at least two surface acoustic wave filter elements;
- wherein at least one of the input terminal side and the output terminal side of said at least two surface acoustic wave filter elements is a common terminal for each of said at least two surface acoustic wave filter elements;
- and
- wherein at least one of said two surface acoustic wave filter elements is constituted of a surface acoustic wave filter including:
- a longitudinally-coupled resonator-type surface acoustic wave filter having a piezoelectric substrate and at least two interdigital transducers disposed on the piezoelectric substrate along the propagation direction of a surface acoustic wave generated therein;
- and
- at least one surface acoustic wave resonator connected between at least one of an input terminal and an output terminal of the surface acoustic wave filter, and said longitudinally-coupled resonator-type surface acoustic wave filter;
- wherein a pass band is generated by utilizing at least one of the resonant modes of said longitudinally-coupled resonator-type surface acoustic wave filter and inductance of said at least one surface acoustic wave resonator.
Dependencies are inferred from the claim text.