US3717877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cavity backed spiral antenna
Assignee: Lockheed Martin Corp
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Filing: 1970-02-27
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Granted: 1973-02-20
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Expires: 1990-02-27
Abstract
Abstract Cavity backed spiral antenna apparatus having an extremely narrow depth. The spiral antenna elements are preferably equiangular and comprise less than a full turn but more than a half turn and are ferrite loaded to result in a cavity depth which is on the order of 1/80 of the wavelength of the highest frequency of interest.
Inventors
- 👤 A Hanninen
- 👤 S Scanlon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:28
CPC Classifications
H; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/16; H01Q9/26; H01Q9/27
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
90 words
A cavity having an aperture; a spiral antenna mounted over said aperture, said spiral antenna including a pair of conducting elements which are coiled in spiral and are equiangular, each of said elements being less than one turn and greater than one half turn, loading means including a sheet of ferrite material mounted within said cavity whereby the cavity depth is on the order of lambda /80 where lambda is the wavelength of the highest frequency of interest; and feed means for coupling energy to and from the spiral antenna.
Claim 2
Dependent Claim
90 words
A cavity having an aperture; a spiral antenna mounted over said aperture, said spiral antenna including a pair of conducting elements which are coiled in spiral and are equiangular, each of said elements being less than one turn and greater than one half turn, loading means including a sheet of ferrite material mounted within said cavity whereby the cavity depth is on the order of lambda /80 where lambda is the wavelength of the highest frequency of interest; and feed means for coupling energy to and from the spiral antenna.
Claim 3
Dependent Claim
90 words
A cavity having an aperture; a spiral antenna mounted over said aperture, said spiral antenna including a pair of conducting elements which are coiled in spiral and are equiangular, each of said elements being less than one turn and greater than one half turn, loading means including a sheet of ferrite material mounted within said cavity whereby the cavity depth is on the order of lambda /80 where lambda is the wavelength of the highest frequency of interest; and feed means for coupling energy to and from the spiral antenna.
Claim 4
Dependent Claim
90 words
A cavity having an aperture; a spiral antenna mounted over said aperture, said spiral antenna including a pair of conducting elements which are coiled in spiral and are equiangular, each of said elements being less than one turn and greater than one half turn, loading means including a sheet of ferrite material mounted within said cavity whereby the cavity depth is on the order of lambda /80 where lambda is the wavelength of the highest frequency of interest; and feed means for coupling energy to and from the spiral antenna.
Claim 5
Dependent Claim
27 words
The invention as set forth in claim 1 wherein said spiral antenna elements are mounted upon a surface of said ferrite sheet which faces the cavity aperture.
References Cited (Backward Citations)
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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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |