US3593225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
L-band switchable narrow bandstop filter
Assignee: United States Department of the Army
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Filing: 1969-09-29
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Granted: 1971-07-13
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Expires: 1989-09-29
Abstract
Abstract An air stripline filter has one or more loosely coupled parallel resonators. Each resonator has a shunt PIN diode tapped thereto. When the diode is forward biased by a reversible bias circuit the narrowband rejection notch of the filter is moved forward in frequency.
Inventors
- 👤 Reed E Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:29
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/201; H01P1/203; H01P1/2039
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
100 words
A switchable, narrow bandstop, stripline filter having at least one resonator loosely coupled to said stripline, wherein said stripline has at least one ground plane; shorting connected between one end of the resonator and the ground plane; and a PIN diode connected between a predetermined point on the resonator and the ground plane; and a bias circuit connected to selectively forward or reverse bias said diode, wherein said filter highly attenuates only signals of a first arrow frequency band when the diode is reversed bias, and highly attenuates only a second narrow frequency band when said diode is forward biased.
Claim 2
Dependent Claim
100 words
A switchable, narrow bandstop, stripline filter having at least one resonator loosely coupled to said stripline, wherein said stripline has at least one ground plane; shorting connected between one end of the resonator and the ground plane; and a PIN diode connected between a predetermined point on the resonator and the ground plane; and a bias circuit connected to selectively forward or reverse bias said diode, wherein said filter highly attenuates only signals of a first arrow frequency band when the diode is reversed bias, and highly attenuates only a second narrow frequency band when said diode is forward biased.
Claim 3
Dependent Claim
36 words
A filter as set forth in claim 1, wherein said filter is an air dielectric stripline having two ground planes; said filter having more than one resonator; and a like number of diodes and shorting means.
Claim 4
Dependent Claim
53 words
A filter as set forth in claim 2 wherein each resonator has a length equal to one-fourth of the wavelength of the midfrequency of said first frequency band; and said predetermined point on each resonator is one sixth of the resonator''s length towards the end of the resonator connected to the shorting means.
References Cited (Backward Citations)
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Cited
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Cited
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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) | 1974-07-12 | 1975-01-11 | 1975-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-12 | 1979-01-11 | 1979-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-12 | 1983-01-11 | 1983-07-13 | $7700.00 | Window Closed / Lapsed |