US4253100A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inverse cassegrain antenna for multiple function radar
Assignee: Thales SA
•
Filing: 1980-01-29
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Granted: 1981-02-24
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Expires: 2000-01-29
Abstract
Abstract Inverse Cassegrain antenna making it possible to use on the one hand the qualities of a conventional fine beam for look-out and tracking functions and making it possible on the other hand to have a widened beam either in the elevation plane or in the bearing plane. According to one embodiment, this antenna is provided with a mirror constituted by two reflector - polarizer elements joined to one another by a hinge which permits the articulation thereof, a remote control device regulating their relative orientation.
Inventors
- 👤 Yves Commault
- 👤 Francois Gautier
- 👤 Robert Pierrot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:28
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/01; H01Q19/00; H01Q19/10; H01Q19/18; H01Q19/19; H01Q19/195; H01Q25/00; H01Q25/002
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
An inverse Cassegrain antenna for a multiple function radar, comprising a primary source of high frequency electromagnetic waves with linear polarization, a curved primary reflector of revolution axis XX for reflecting the wave coming directly from the primary source and for selectively transmitting the electromagnetic wave having a crossed linear polarization, the primary source being essentially arranged in the focus of said primary reflector, a polarization rotation mirror ensuring the return to the primary reflector of the reflected radiation which has undergone a rotation of its polarization plane, wherein the polarization rotation mirror is formed by a plurality of reflector-polarizer elements, which are articulated with respect to one another and wherein said elements are associated with means for controlling their relative position.
Claim 2
Dependent Claim
122 words
An inverse Cassegrain antenna for a multiple function radar, comprising a primary source of high frequency electromagnetic waves with linear polarization, a curved primary reflector of revolution axis XX for reflecting the wave coming directly from the primary source and for selectively transmitting the electromagnetic wave having a crossed linear polarization, the primary source being essentially arranged in the focus of said primary reflector, a polarization rotation mirror ensuring the return to the primary reflector of the reflected radiation which has undergone a rotation of its polarization plane, wherein the polarization rotation mirror is formed by a plurality of reflector-polarizer elements, which are articulated with respect to one another and wherein said elements are associated with means for controlling their relative position.
Claim 3
Dependent Claim
28 words
An antenna according to claim 1, wherein the polarization rotation mirror is formed by two reflector-polarizer elements articulated about a hinge perpendicular to a diameter of the antenna.
Claim 4
Dependent Claim
17 words
An antenna according to claim 2, wherein the hinge is positioned at two thirds of said diameter.
Claim 5
Dependent Claim
29 words
An antenna according to claim 1, wherein the polarization rotation mirror is formed by three plane reflector-polarizer elements articulated about two hinges perpendicular to a diameter of the antenna.
Claim 6
Dependent Claim
32 words
An antenna according to claim 4, wherein the hinge is positioned in accordance with a diameter of the antenna, the other hinge being positioned at essentially two thirds of the said diameter.
Claim 7
Dependent Claim
21 words
An antenna according to claim 4, wherein the two hinges are arranged symmetrically with respect to a diameter of the antenna.
Claim 8
Dependent Claim
20 words
An antenna according to claim 1, wherein the hinges are perpendicular to the vertical plane of symmetry of the antenna.
Claim 9
Dependent Claim
24 words
An antenna according to claim 1, wherein the hinges form an angle differing from (π/2) with the vertical plane of symmetry of the antenna.
Claim 10
Dependent Claim
59 words
An antenna according to claim 1, wherein the reflector-polarizer elements are constituted by a planar metal plate in front of which and at a distance equal to k(λ/4) is arranged a planar layer comprising metal wires inclined by 45° relative to the instant radiation polarization direction, λ being the operating wavelength of the antenna and k an uneven integer.
Claim 11
Dependent Claim
28 words
An antenna according to claim 1, wherein the reflector-polarizer elements are constituted by metal plates, which are also inclined by 45° relative to the incident radiation polarization direction.
Claim 12
Dependent Claim
84 words
An antenna according to claim 1, wherein the means controlling the relative positioning of the reflector-polarizer elements comprise a motor fixed to the mirror and whose spindle is constituted by a worm screw having a sliding contact driven in translation by said worm screw, the sliding contact having a pointer which moves in a direction perpendicular to the sliding contact translation direction, the moving pointer having one end engaged in a slide located on the back of the reflecting surface of the reflector-polarizer element.
References Cited (Backward Citations)
US3254342A
Cited
US3771160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |