US5894251A
Expired / Lapsed
US
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High frequency filter having saw and dielectric filters with different frequency temperature characteristic signs
Assignee: Skyworks Filter Solutions Japan Co Ltd
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Filing: 1997-06-11
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Granted: 1999-04-13
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Expires: 2017-06-11
Abstract
Abstract 36° -rotated Y-cut X-propagation lithium niobate substrate (LiNbO 3 ) was used as a piezoelectric substrate to compose a surface acoustic wave filter and is connected with a dielectric filter in series. The dielectric filter having a sign of the frequency temperature characteristic which is opposite to that of the surface acoustic wave filter was used. Accordingly, a high frequency filter, comprising a surface acoustic filter and a dielectric filter connected in series, which can secure sufficient attenuation without an increase in the insertion loss within the band can be provided.
Inventors
- 👤 Yutaka Taguchi
- 👤 Kazuo Eda
- 👤 Shun-ichi Seki
- 👤 Keiji Onishi
- 👤 Toru Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:02
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/64; H03H9/6423; H03H9/6433; H03H9/6483; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02834
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
39 words
A high frequency filter comprising a surface acoustic wave filter and a dielectric filter connected in series, wherein a sign of the frequency temperature characteristic of said surface acoustic wave filter is different from that of said dielectric filter.
Claim 2
Dependent Claim
39 words
A high frequency filter comprising a surface acoustic wave filter and a dielectric filter connected in series, wherein a sign of the frequency temperature characteristic of said surface acoustic wave filter is different from that of said dielectric filter.
Claim 3
Dependent Claim
33 words
A high frequency filter as claimed in claim 1, wherein the absolute value of the frequency temperature characteristic of a surface acoustic wave filter is substantially same as that of the dielectric filter.
Claim 4
Dependent Claim
24 words
A high frequency filter as claimed in claim 1, wherein said surface wave filter comprises an interdigital transducer (IDT) formed on a piezoelectric substrate.
Claim 5
Dependent Claim
34 words
A high frequency filter as claimed in claim 3, wherein said piezoelectric substrate is one selected from a group consisting of lithium tantalate (LiTaO 3 ), lithium niobate (LiNbO 3 ) and crystal substrate.
Claim 6
Dependent Claim
18 words
A high frequency filter as claimed in claim 3, wherein said interdigital transducer (IDT) is an aluminum electrode.
Claim 7
Dependent Claim
18 words
A high frequency filter as claimed in claim 1, wherein said dielectric filter is a dielectric notch filter.
Claim 8
Dependent Claim
24 words
A high frequency filter as claimed in claim 6, wherein said dielectric filter is composed of a quarter wave length open-ended dielectric coaxial resonator.
Claim 9
Dependent Claim
19 words
A high frequency filter as claimed in claim 1, wherein said surface acoustic wave filter is a band-pass filter.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-04-12 | 2002-10-12 | 2003-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-12 | 2006-10-12 | 2007-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-04-12 | 2010-10-12 | 2011-04-13 | $7700.00 | Window Closed / Lapsed |