US3820117A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency extension of circularly polarized antenna
Assignee: Bendix Corp
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Filing: 1972-12-26
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Granted: 1974-06-25
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Expires: 1992-12-26
Abstract
Abstract The frequency response of a cavity-backed planar microwave antenna having an element including a pair of spiral antenna tracks fixed to a substrate of insulating material is substantially extended by connecting a pair of cavity-backed outwardly extending dipole elements to the outer ends of each of said spiral tracks. The lower range of useful frequency response is thereby changed from a minimum operating frequency wherein the diameter of the spiral tracks constitutes approximately one-half wave length to a value wherein one-half wave length is approximately equal to the width of the antenna elements including the dipoles. This composite structure may be curved to some degree to enable it to conform to the inside surface of a curved radome.
Inventors
- 👤 R Hall
- 👤 R Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:33
CPC Classifications
H; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/16; H01Q9/26; H01Q9/27; H01Q1/00; H01Q1/40; H01Q1/405; H01Q21/00; H01Q21/29
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
A wide band microwave antenna assembly comprising: a planar spiral antenna mounted on a substrate of insulating material, said antenna including a pair of interlaced spiral elements having terminals near the axis of said assembly, a cavity structure of generally cylindrical configuration supporting said antenna element and positioned at the back of said planar spiral antenna, and a lower frequency linearly polarized antenna extension comprising a cavity-backed dipole element electrically connected to the outside ends of each of said spiral elements.
Claim 2
Dependent Claim
81 words
A wide band microwave antenna assembly comprising: a planar spiral antenna mounted on a substrate of insulating material, said antenna including a pair of interlaced spiral elements having terminals near the axis of said assembly, a cavity structure of generally cylindrical configuration supporting said antenna element and positioned at the back of said planar spiral antenna, and a lower frequency linearly polarized antenna extension comprising a cavity-backed dipole element electrically connected to the outside ends of each of said spiral elements.
Claim 3
Dependent Claim
81 words
A wide band microwave antenna assembly comprising: a cylindrical cavity, an antenna element overlying said cavity including a substrate of insulating material and a pair of interlaced spiral antenna tracks fixed to said substrate, and a lower frequency extension comprising a cavity-backed dipole element connected to the outside end of each of said tracks such that the overall width of the assembly is approximately one-half wave length at the lowest frequency for which the antenna is expected to provide significant gain.
Claim 4
Dependent Claim
81 words
A wide band microwave antenna assembly comprising: a cylindrical cavity, an antenna element overlying said cavity including a substrate of insulating material and a pair of interlaced spiral antenna tracks fixed to said substrate, and a lower frequency extension comprising a cavity-backed dipole element connected to the outside end of each of said tracks such that the overall width of the assembly is approximately one-half wave length at the lowest frequency for which the antenna is expected to provide significant gain.
Claim 5
Dependent Claim
27 words
A wide band antenna assembly as set forth in claim 2 wherein said cavity and the cavities backing said dipole elements are lined with microwave absorber material.
Claim 6
Dependent Claim
28 words
A wide band antenna assembly as set forth in claim 2 wherein said spiral track and said dipole elements are conformed to fit against a rounded radome structure.
Claim 7
Dependent Claim
22 words
A wide band antenna assembly as set forth in claim 2 wherein said substrate is dome-shaped and said dipole elements are curved.
Claim 8
Dependent Claim
39 words
A wide band antenna assembly as set forth in claim 2 wherein the height of said antenna tracks and dipole members from the back walls of their respective cavities is less than one-quarter wave length over the frequencies received.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |