US5093638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Unbalanced saw filter
Assignee: CTS Corp
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Filing: 1990-11-05
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Granted: 1992-03-03
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Expires: 2010-11-05
Abstract
Abstract An unbalanced surface acoustic wave (SAW) resonator-filter is achieved by using a predetermined length of unbalanced transmission line to define a ground potential and permit two SAW resonators and such transmission line to function together as an unbalanced filter.
Inventors
- 👤 Robert G. Kinsman
- 👤 Richard S. Bickham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:02
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/0023; H03H9/0028; H03H9/0085; H03H9/009
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
An RF filter comprising: A) a first SAW resonator having a first resonant frequency; B) a second SAW resonator having a second resonant frequency; and, C) a grounded transmission line, having a length substantially equal to one half the average wavelength of the first and second frequencies, connected in series with the first SAW resonator; an input and an output of the RF filter defined by opposing ends of a parallel circuit formed by interconnection of the second SAW resonator with opposing ends of the series connected first SAW resonator and grounded transmission line, and an RF filter ground defined by a ground of the grounded transmission line.
Claim 2
Dependent Claim
108 words
An RF filter comprising: A) a first SAW resonator having a first resonant frequency; B) a second SAW resonator having a second resonant frequency; and, C) a grounded transmission line, having a length substantially equal to one half the average wavelength of the first and second frequencies, connected in series with the first SAW resonator; an input and an output of the RF filter defined by opposing ends of a parallel circuit formed by interconnection of the second SAW resonator with opposing ends of the series connected first SAW resonator and grounded transmission line, and an RF filter ground defined by a ground of the grounded transmission line.
Claim 3
Dependent Claim
26 words
The RF filter as in claim 1 wherein the grounded transmission line has a length substantially equal to an odd-numbered multiple of one-half the average wavelength.
Claim 4
Dependent Claim
30 words
The RF filter as in claim 1 wherein the grounded transmission line comprises a meander line on a substrate and a ground plane on the opposite side of the substrate.
Claim 5
Dependent Claim
14 words
The RF filter as in claim 4 wherein the substrate comprises a piezoelectric material.
Claim 6
Dependent Claim
142 words
An RF filter comprising; A) a first and second SAW resonator, each having a first resonant frequency, connected in series at a first midpoint to provide a first series circuit having opposing ends; B) a third and fourth SAW resonator, each having a second resonant frequency, connected in series at a second midpoint to provide a second series circuit having opposing ends; C) a grounded transmission line having a length substantially equal to one half the average wavelength of the first and second resonant frequencies, connected between the first and second midpoints, an input and an output of the RF filter defined by opposing ends of a parallel circuit formed by interconnection of the opposing ends of the first series circuit with opposing ends of the second series circuit, and an RF ground defined by a ground of the grounded transmission line.
Claim 7
Dependent Claim
142 words
An RF filter comprising; A) a first and second SAW resonator, each having a first resonant frequency, connected in series at a first midpoint to provide a first series circuit having opposing ends; B) a third and fourth SAW resonator, each having a second resonant frequency, connected in series at a second midpoint to provide a second series circuit having opposing ends; C) a grounded transmission line having a length substantially equal to one half the average wavelength of the first and second resonant frequencies, connected between the first and second midpoints, an input and an output of the RF filter defined by opposing ends of a parallel circuit formed by interconnection of the opposing ends of the first series circuit with opposing ends of the second series circuit, and an RF ground defined by a ground of the grounded transmission line.
Claim 8
Dependent Claim
26 words
The RF filter as in claim 5 wherein the grounded transmission line has a length substantially equal to an odd-numbered multiple of one-half the average wavelength.
Claim 9
Dependent Claim
30 words
The RF filter as in claim 5 wherein the grounded transmission line comprises a meander line on a substrate and a ground plane on the opposite side of the substrate.
Claim 10
Dependent Claim
14 words
The RF filter as in claim 7 wherein the substrate comprises a piezoelectric material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-03 | 1995-09-02 | 1996-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-03 | 1999-09-02 | 2000-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-03 | 2003-09-02 | 2004-03-03 | $7700.00 | Window Closed / Lapsed |