US4400701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Common antenna for primary and secondary radar
Assignee: Thales SA
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Filing: 1981-01-23
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Granted: 1983-08-23
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Expires: 2001-01-23
Abstract
Abstract A bifunctional antenna of a primary/secondary radar system comprises a reflector having a concave front surface illuminated by a source of primary radiation and formed with a row of circular ports along a horizontal generatrix, the ports lying forwardly of respective cavities or waveguides of cylindrical configuration excitable to emit circularly polarized secondary radiation. In some embodiments the polarization may be changed to a linear or an elliptical mode under the control of inserts rotatable about the cavity axis.
Inventors
- 👤 Albert Dupressoir
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:04
CPC Classifications
H; H01; H01Q; H01Q21/00; H01Q21/28; H01Q21/06; H01Q21/061; H01Q21/067; H01Q25/00; H01Q9/00; H01Q9/04; H01Q9/16; H01Q9/26; H01Q9/27; Y; Y10; Y10S; Y10S430/00; Y10S430/165
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
A bifunctional antenna for a primary/secondary radar system, comprising: a reflector formed of a body of dielectric material with a reflective surface of crossed wires, said reflector being adapted to be illuminated by a primary source of outgoing radiation for detecting a remote target; a row of emitters of secondary radiation disposed along a generatrix of said front surface intersecting a boresight axis, said emitters being formed by circular ports in said front surface backed by cylindrical cavities having walls integral with said body, said cavities being coaxial with said ports and having axes extending in radial directions of said front surface; and wave-control means in said cavities adapted to establish a circular mode of polarization for the secondary radiation emitted thereby.
Claim 2
Dependent Claim
122 words
A bifunctional antenna for a primary/secondary radar system, comprising: a reflector formed of a body of dielectric material with a reflective surface of crossed wires, said reflector being adapted to be illuminated by a primary source of outgoing radiation for detecting a remote target; a row of emitters of secondary radiation disposed along a generatrix of said front surface intersecting a boresight axis, said emitters being formed by circular ports in said front surface backed by cylindrical cavities having walls integral with said body, said cavities being coaxial with said ports and having axes extending in radial directions of said front surface; and wave-control means in said cavities adapted to establish a circular mode of polarization for the secondary radiation emitted thereby.
Claim 3
Dependent Claim
34 words
An antenna as defined in claim 1 wherein said wave-control means comprises an insert in each cavity rotatable about said axis thereof for selectively changing said circular mode of polarization to a different mode.
Claim 4
Dependent Claim
40 words
An antenna as defined in claim 2 wherein said emitters each include a linear exciter extending radially into said cavity at a location set back from said port thereof, said insert being located between said exciter and said front surface.
Claim 5
Dependent Claim
15 words
An antenna as defined in claim 3 wherein said insert is disposed within said port.
Claim 6
Dependent Claim
17 words
An antenna as defined in claim 3 wherein said insert comprises a planar grid of parallel conductors.
Claim 7
Dependent Claim
19 words
An antenna as defined in claim 3 wherein said insert is a flat dielectric plate centered on said axis.
Claim 8
Dependent Claim
13 words
An antenna as defined in claim 6 wherein said plate is substantially H-shaped.
Claim 9
Dependent Claim
23 words
An antenna as defined in claim 1 wherein said wave-control means comprises an excitation element in each cavity coiled about the axis thereof.
Claim 10
Dependent Claim
18 words
An antenna as defined in claim 8 wherein said excitation element is a helix tapering toward said port.
Claim 11
Dependent Claim
24 words
An antenna as defined in claim 8 wherein said excitation element is a spiral located in said port at the front of each cavity.
Claim 12
Dependent Claim
21 words
An antenna as defined in claim 1 wherein said cavities are dimensioned to establish a short-circuit plane at said front surface.
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) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |