Patent US3919673A successfully refreshed from Google Patents.
US3919673A
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Nonreciprocal absorption filter
Assignee: AT&T Inc
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Filing: 1974-06-05
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Granted: 1975-11-11
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Expires: 1994-06-05
Abstract
Abstract A nonreciprocal absorption filter (i.e., narrow band isolator) is disclosed comprising a magnetically biased gyromagnetic element located off the center axis of a conductively bounded waveguide. For one direction of wave propagation, the gyromagnetic element forms a dielectric resonator which is critically coupled to the signal and absorbs wave energy over a narrow band of frequencies within a given, broader band of interest. For wave propagation in the opposite direction, the field displacement effect produced by the element decouples the signal from the cavity and substantially no absorption takes place.
Inventors
- 👤 Joseph John Kostelnick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:01
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/215; H01J; H01J1/00; H01J1/02; H01J1/32
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
A nonreciprocal filter including: a section of waveguide whose cross-sectional dimensions are proportioned to permit the propagation of electromagnetic wave energy over a defined frequency band of interest; and means for attenuating wave energy within a selected portion of said band of interest for one direction of wave propagation comprising: an element of gyromagnetic material magnetically biased below gyromagnetic resonance with respect to the frequency band of interest and positioned within said section to produce a region of substantial field intensity differential in said wave energy for opposite directions of wave propagation, and for simultaneously forming a dielectric resonator that is critically coupled to said wave energy over said selected portion of said band of interest for one direction of propagation while being substantially transparent to said wave energy for the opposite direction of wave propagation; said section of waveguide being substantially free of any other attenuating means.
Claim 2
Dependent Claim
148 words
A nonreciprocal filter including: a section of waveguide whose cross-sectional dimensions are proportioned to permit the propagation of electromagnetic wave energy over a defined frequency band of interest; and means for attenuating wave energy within a selected portion of said band of interest for one direction of wave propagation comprising: an element of gyromagnetic material magnetically biased below gyromagnetic resonance with respect to the frequency band of interest and positioned within said section to produce a region of substantial field intensity differential in said wave energy for opposite directions of wave propagation, and for simultaneously forming a dielectric resonator that is critically coupled to said wave energy over said selected portion of said band of interest for one direction of propagation while being substantially transparent to said wave energy for the opposite direction of wave propagation; said section of waveguide being substantially free of any other attenuating means.
Claim 3
Dependent Claim
19 words
The filter according to claim 1 including a metallic post within said section of waveguide for tuning said element.
Claim 4
Dependent Claim
42 words
IN combination: a plurality of filters, each according to claim 1, longitudinally distributed along said waveguide such that each filter is spaced apart from the next adjacent filter a distance corresponding to one wavelength at the center of said band of interest.
Claim 5
Dependent Claim
15 words
The filter according to claim 1 wherein said waveguide is a conductively bounded rectangular waveguide.
Claim 6
Dependent Claim
38 words
The filter according to claim 4 wherein said element of gyromagnetic material has a circular cylindrical shape; and wherein said element is mounted on one of the wide walls of said waveguide with the cylinder axis normal thereto.
Claim 7
Dependent Claim
20 words
The filter according to claim 5 wherein said element is transversely displaced with respect to the center of said waveguide.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |