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US 7,741,931 B2Granted
Acoustic wave device, resonator and filter
AssigneesFujitsu Media Devices Limited, Fujitsu Limited
InventorsSatoru Matsuda, Michio Miura, Shogo Inoue, Takashi Matsuda, Masanori Ueda, Seiichi Mitobe
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Abstract
A filter includes a parallel resonator having first comb electrodes provided on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes, and a series resonator having second comb electrodes provided on the piezoelectric substrate and a second dielectric film covers the second comb electrodes and is made of a material identical to that of the first dielectric film. The first dielectric film has a different thickness from that of the second dielectric film.
Claims15
A filter comprising:
- each of parallel resonators having first comb electrodes provided on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes;
- and
- each of series resonators having second comb electrodes provided on the piezoelectric substrate and a second dielectric film that covers the second comb electrodes and is made of a material identical to that of the first dielectric film,
- each of the first dielectric films having a thickness smaller than a thickness of each of the second dielectric films.
1 more element
A filter comprising:
- a first acoustic wave filter having first comb electrodes provided on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes;
- and
- a second acoustic wave filter having second comb electrodes provided on the piezoelectric substrate and a second dielectric film covers the second comb electrodes and is made of a material identical to that of the first dielectric film,
- the first dielectric film having a thickness smaller than a thickness of the second dielectric film,
- the first and second acoustic wave filters being connected in series;
- the first acoustic wave filter being an input side of the filter;
- and
- the second acoustic wave filter being an output side of the filter;
- wherein the first and second acoustic wave filter are respectively multimode acoustic wave filters.
6 more elements
A filter comprising:
- a filter acoustic wave filter having first comb electrodes provide on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes;
- and
- a second acoustic wave filter having second comb electrode providing on the piezoelectric substrate and a second dielectric film covers the second comb electrodes and is made of a material identical to that of the first dielectric film,
- the first dielectric film having a thickness smaller than a thickness of the second dielectric film,
- the first and second acoustic wave filters being connected in series;
- the first acoustic wave filter being an input side of the filter;
- the second acoustic wave filter being an output side of the filter;
- and
- a third dielectric film that is provided on the first an second dielectric films,
- the third dielectric film having an acoustic velocity greater than acoustic velocities of the first and second dielectric films.
7 more elements
A duplexer comprising:
- a first acoustic wave filter having first comb electrodes provided on a piezoelectric substrate and a first dielectric film that covers the first comb electrodes;
- and
- a second acoustic wave filter having second comb electrode provided on the piezoelectric substrate and a second dielectric film covers the second comb electrodes and is made of a material identical to that of the first dielectric film,
- the first dielectric film having a thickness smaller than a thickness of the second dielectric film,
- the first and second acoustic wave filters being connected at a common terminal;
- the first acoustic wave filter being a high-frequency-side filter of the duplexer;
- the second acoustic wave filter being a low frequency-side filter of the duplexer;
- and
- the first and second acoustic wave filters being ladder filters.
6 more elements
Dependencies are inferred from the claim text.