US3958246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circular retrodirective array
Assignee: Calspan Corp
•
Filing: 1974-07-05
•
Granted: 1976-05-18
•
Expires: 1994-07-05
Abstract
Abstract The retrodirective array antenna of the present invention employs a circular, focusing parallel plate lens to interconnect array elements, thus producing a body with an inherently large radar cross section. By modulating the radiated signal from such an array, it is possible to meet the requirements for passive beacon and data transmission applications. Information transmittal is accomplished via the selection of the modulation function.
Inventors
- 👤 Robert J. Wohlers
- 👤 Stephen N. Andre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:55
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/75; G01S13/751; G01S13/756; H; H01; H01Q; H01Q19/00; H01Q19/06; H01Q19/062; H01Q3/00; H01Q3/44; H01Q3/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
77 words
A retrodirective array antenna comprising: housing means including a base plate and a cover plate which are separated by spacer means to define a substantially cylindrical chamber; a plurality of pairs of diametrically located array elements circumferentially located on said cover plate to extend outwardly therefrom and having probe means extending into said chamber; and lens means located within said chamber for focusing and directing energy between said elements of said pairs of diametrically located array elements.
Claim 2
Dependent Claim
77 words
A retrodirective array antenna comprising: housing means including a base plate and a cover plate which are separated by spacer means to define a substantially cylindrical chamber; a plurality of pairs of diametrically located array elements circumferentially located on said cover plate to extend outwardly therefrom and having probe means extending into said chamber; and lens means located within said chamber for focusing and directing energy between said elements of said pairs of diametrically located array elements.
Claim 3
Dependent Claim
11 words
The antenna of claim 1 wherein said array elements are monopoles.
Claim 4
Dependent Claim
15 words
The antenna of claim 1 wherein said lens means is a non-homogeneous Maxwell fisheye lens.
Claim 5
Dependent Claim
14 words
The antenna of claim 1 wherein said lens means is an equivalent fisheye lens.
Claim 6
Dependent Claim
17 words
The antenna of claim 1 further comprising means for modulating the radar cross section of said antenna.
Claim 7
Dependent Claim
25 words
The antenna of claim 5 wherein said means for modulating the radar cross section includes solid state devices whose electrical characteristics can be electronically controlled.
Claim 8
Dependent Claim
11 words
The antenna of claim 6 wherein said array elements are monopoles.
Claim 9
Dependent Claim
15 words
The antenna of claim 6 wherein said lens means is a non-homogeneous Maxwell fisheye lens.
Claim 10
Dependent Claim
14 words
The antenna of claim 6 wherein said lens means is an equivalent fisheye lens.
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) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |