Piezoelectric filter
AssigneeMurata Manufacturing Co., Ltd.
InventorKimio Masaie
Life of this patent
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Abstract
A piezoelectric filter for use in electrical and electronic equipment which includes a substrate of piezoelectric material, and electrode members provided on first and second surfaces of the substrate so as to form at least one set of resonator including a multi-mode resonator and a single resonator of the thickness-vibration, energy-trapping type. The multi-mode resonator serves as a series resonance element of a ladder type filter through utilization of the oblique or anti-symmetrical mode resonance of the multi-mode resonator, while the single resonator is used as a parallel resonance element of the ladder type filter.
Claims7
A piezoelectric filter, comprising:
- a piezoelectric substrate having first and second main surfaces;
- electrode means disposed on said main surfaces and defining at least one set of piezoelectric resonators, said set including an energy-trapping multi-mode resonator and a thickness-vibration, energy-trapping type single resonator;
- and
- conductive means disposed on said main surfaces of said substrate defining an input terminal, an output terminal and a third terminal and defining conductive paths connecting said energy-trapping multi-mode resonator in series between said input terminal and said output terminal, and connecting said thickness-vibration energy-trapping type single resonator between said third terminal and one of said input terminal and said output terminal.
Dependencies are inferred from the claim text.