US3938162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable beamwidth antenna
Assignee: National Aeronautics and Space Administration
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Filing: 1974-08-27
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Granted: 1976-02-10
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Expires: 1994-08-27
Abstract
Abstract An antenna system for single or plural beams providing continuously variable beamwidth selectively in one or both of two orthogonal senses, i.e., azimuth and elevation, for either communications or angle-tracking. The system includes two parabolic cylindrical reflectors, which are respectively a main reflector and a sub-reflector; the reflectors are positioned with the focal axes thereof orthogonally. A point or multibeam (e.g., monopulse) feed is mounted adjacent the main reflector on the focal axis of the sub-reflector in the Airy disc of the system. Beamwidth is controlled using telescoping sections on the main and sub-reflectors to control the size of the surface areas thereof. Simultaneous operation of the telescoping sections of the reflector and sub-reflector provides bidirectional zooming of the beam without distortion while individual operation of the sections of the reflectors permits unidirectional zooming. Bidirectional zooming of beams from the multibeam feed requires rotating the position of the multibeam feed as the Airy disc changes during adjustment of the telescoping sections.
Inventors
- 👤 Richard F. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:02
CPC Classifications
H; H01; H01Q; H01Q19/00; H01Q19/20; H01Q25/00; H01Q25/002; H01Q3/00; H01Q3/01
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
104 words
An antenna comprising: a parabolic cylindrical main reflector having a first focal axis; a cylindrical sub-reflector having a second focal axis; said main reflector and sub-reflector being positioned with said first and second axes orthogonally and a point source on said second axis being an image of a line source on said first axis; and a multibeam feed for transducing electromagnetic waves, said feed being positioned in a plane of an Airy disc of the antenna, said waves being reflected between said subreflector and said main reflector, said Airy disc lying on said second focal axis and said plane being oblique to said axes.
Claim 2
Dependent Claim
104 words
An antenna comprising: a parabolic cylindrical main reflector having a first focal axis; a cylindrical sub-reflector having a second focal axis; said main reflector and sub-reflector being positioned with said first and second axes orthogonally and a point source on said second axis being an image of a line source on said first axis; and a multibeam feed for transducing electromagnetic waves, said feed being positioned in a plane of an Airy disc of the antenna, said waves being reflected between said subreflector and said main reflector, said Airy disc lying on said second focal axis and said plane being oblique to said axes.
Claim 3
Dependent Claim
11 words
The antenna of claim 1 wherein said cylindrical sub-reflector is parabolic.
Claim 4
Dependent Claim
13 words
The antenna of claim 1 wherein said multibeam feed is a monopulse feed.
Claim 5
Dependent Claim
57 words
The antenna of claim 1 wherein said main reflector includes a surface having a first surface area, said sub-reflector includes a surface having a second surface area, and means for controlling the size of the surface area of one of the reflectors to vary the aperture size of the antenna in a coordinate direction of the antenna.
Claim 6
Dependent Claim
36 words
The antenna of claim 4 further including means for rotating the position of said multibeam feed for changes in position of said Airy disc as a result of changes of the surface areas of the reflectors.
Claim 7
Dependent Claim
45 words
The antenna of claim 5 wherein said means for controlling controls the sub-reflector, and said means for rotating includes means for controlling the rotational position of said feed about a line parallel to said first axis as a function of the size of said sub-reflector.
Claim 8
Dependent Claim
24 words
The antenna of claim 4 wherein said means for controlling includes means for adjusting the axial lengths of said main reflector and said sub-reflector.
Claim 9
Dependent Claim
20 words
The antenna of claim 4 wherein said means for controlling includes means for adjusting the axial length of said sub-reflector.
Claim 10
Dependent Claim
21 words
The antenna of claim 4 wherein said means for controlling includes means for adjusting the axial length of said main reflector.
Claim 11
Dependent Claim
29 words
The antenna of claim 9 wherein said controlling means includes for adjusting a pair of telescoping sections on said main reflector symmetrically relative to the intersection of said axes.
Claim 12
Dependent Claim
26 words
The antenna of claim 9 wherein said adjusting means includes a telescoping section contiguous to said main reflector and slidable to adjust the axial length thereof.
Claim 13
Dependent Claim
144 words
An antenna comprising: a parabolic cylindrical main reflector having a first focal axis; a cylindrical sub-reflecor having a second focal axis; said main reflector and sub-reflector being positioned with said first and second axes orthogonally and a point source of said second axis being an image of a line source on said first axis; a feed for transducing waves of electromagnetic energy positioned on said second axis to form a pattern that irradiates said sub-reflector and is reflected between said sub-reflector and main reflector to illuminate said main reflector; and means for controlling the size of the surface area of at least one of said reflectors, wherein at least one of said main reflector and said sub-reflector includes a telescoping section and a fixed section, said telescoping secton adapted to slide contiguously to said fixed portion whereby bidirectional zooming of a beam is provided.
Claim 14
Dependent Claim
144 words
An antenna comprising: a parabolic cylindrical main reflector having a first focal axis; a cylindrical sub-reflecor having a second focal axis; said main reflector and sub-reflector being positioned with said first and second axes orthogonally and a point source of said second axis being an image of a line source on said first axis; a feed for transducing waves of electromagnetic energy positioned on said second axis to form a pattern that irradiates said sub-reflector and is reflected between said sub-reflector and main reflector to illuminate said main reflector; and means for controlling the size of the surface area of at least one of said reflectors, wherein at least one of said main reflector and said sub-reflector includes a telescoping section and a fixed section, said telescoping secton adapted to slide contiguously to said fixed portion whereby bidirectional zooming of a beam is provided.
Claim 15
Dependent Claim
11 words
The antenna of claim 12 wherein said cylindrical sub-reflector is parabolic.
Claim 16
Dependent Claim
36 words
The antenna of claim 12 wherein said telescoping section is driven by a rack and pinion mechanism, a pinion being secured to said fixed section and rotated to drive a rack fixed to said telescoping section.
Claim 17
Dependent Claim
147 words
A double parabolic cylinder antenna of the type having a parabolic cylindrical main reflector and a parabolic cylindrical sub-reflector, said reflectors positioned with their focal axes orthogonally and a point source on said subreflector focal axis being an image of a line source on said main reflector focal axis, and a feed for transducing electromagnetic waves positioned on said sub-reflector focal axis to form a pattern that irradiates said sub-reflector, said pattern being reflected between said main reflector and sub-reflector to illuminate said main reflector, the improvement comprising: means for selectively controlling the size of the surface areas of said sub-reflector and main reflector to provide continuous bidirectional zooming of the pattern, wherein the feed comprises a multibeam feed positioned entirely within an Airy disc of said antenna; and means for rotating the position of said feed so that it remains within said Airy disc during zooming.
Claim 18
Dependent Claim
147 words
A double parabolic cylinder antenna of the type having a parabolic cylindrical main reflector and a parabolic cylindrical sub-reflector, said reflectors positioned with their focal axes orthogonally and a point source on said subreflector focal axis being an image of a line source on said main reflector focal axis, and a feed for transducing electromagnetic waves positioned on said sub-reflector focal axis to form a pattern that irradiates said sub-reflector, said pattern being reflected between said main reflector and sub-reflector to illuminate said main reflector, the improvement comprising: means for selectively controlling the size of the surface areas of said sub-reflector and main reflector to provide continuous bidirectional zooming of the pattern, wherein the feed comprises a multibeam feed positioned entirely within an Airy disc of said antenna; and means for rotating the position of said feed so that it remains within said Airy disc during zooming.
Claim 19
Dependent Claim
85 words
An antenna comprising: a parabolic cylinder main reflector having a first focal axis; a parabolic cylinder sub-reflector having a second focal axis, said reflector and sub-reflector positioned with their axes orthogonally, said sub-reflector intersecting said first axis and said main reflector intersecting said second axis; a feed for transducing electromagnectic waves positioned tangentially to said main reflector along said second axis and irradiating said sub-reflector; and means for adjusting the size of the surface area of at least one of said reflector and said sub-reflector.
Claim 20
Dependent Claim
85 words
An antenna comprising: a parabolic cylinder main reflector having a first focal axis; a parabolic cylinder sub-reflector having a second focal axis, said reflector and sub-reflector positioned with their axes orthogonally, said sub-reflector intersecting said first axis and said main reflector intersecting said second axis; a feed for transducing electromagnectic waves positioned tangentially to said main reflector along said second axis and irradiating said sub-reflector; and means for adjusting the size of the surface area of at least one of said reflector and said sub-reflector.
Claim 21
Dependent Claim
19 words
The antenna of claim 16 wherein said means includes means for adjusting the axial length of said main reflector.
Claim 22
Dependent Claim
18 words
The antenna of claim 16 wherein said means includes means for adjusting the axial length of said sub-reflector.
Claim 23
Dependent Claim
23 words
The antenna of claim 16 wherein said means includes means for adjusting the axial lengths of both said main reflector and said sub-reflector.
Claim 24
Dependent Claim
84 words
A reflector for an antenna system, said reflector comprising: a first parabolic cylinder having a first focal axis; a second parabolic cylinder having a second focal axis; said first and second parabolic cylinders positioned with said first and second axes orthogonally; said first parabolic cylinder being truncated by a plane tangent to said second parabolic cylinder and parallel to said first focal axis; and means for adjusting the size of the suurface area of at least one of said first and second parabolic cylinders.
Claim 25
Dependent Claim
84 words
A reflector for an antenna system, said reflector comprising: a first parabolic cylinder having a first focal axis; a second parabolic cylinder having a second focal axis; said first and second parabolic cylinders positioned with said first and second axes orthogonally; said first parabolic cylinder being truncated by a plane tangent to said second parabolic cylinder and parallel to said first focal axis; and means for adjusting the size of the suurface area of at least one of said first and second parabolic cylinders.
Claim 26
Dependent Claim
23 words
The reflector of claim 20 including a feed for transducing electromagnetic waves, said feed positioned along said second axis adjacent said first reflector.
Claim 27
Dependent Claim
21 words
The reflector of claim 20 wherein said means for controlling includes means for adjusting the axial length of said first cylinder.
Claim 28
Dependent Claim
21 words
The reflector of claim 22 wherein said means for controlling includes means for adjusting the axial length of said second cylinder.
Claim 29
Dependent Claim
34 words
The reflector of claim 20 wherein said first and second cylinders are further positioned so that a point source on said second axis forms an image of a line source on said first axis.
Claim 30
Dependent Claim
28 words
The reflector of claim 20, wherein said means includes means for adjusting the axial length of at least one of said cylinders parallel to the focal axis thereof.
Claim 31
Dependent Claim
85 words
An antenna comprising: a parabolic cylinder main reflector having a first focal axis; a parabolic cylinder sub-reflector having a second focal axis, said reflector and sub-reflector positioned with their axes orthogonally, said sub-reflector intersecting said first axis and said main reflector intersecting said second axis; a feed for transducing electromagnetic waves positioned tangentially to said main reflector along said second axis and irradiating said sub-reflector; and means for adjusting the axial length of at least one of said cylinders parallel to the focal axis thereof.
Claim 32
Dependent Claim
85 words
An antenna comprising: a parabolic cylinder main reflector having a first focal axis; a parabolic cylinder sub-reflector having a second focal axis, said reflector and sub-reflector positioned with their axes orthogonally, said sub-reflector intersecting said first axis and said main reflector intersecting said second axis; a feed for transducing electromagnetic waves positioned tangentially to said main reflector along said second axis and irradiating said sub-reflector; and means for adjusting the axial length of at least one of said cylinders parallel to the focal axis thereof.
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) | 1979-02-09 | 1979-08-11 | 1980-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-09 | 1983-08-11 | 1984-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-09 | 1987-08-11 | 1988-02-10 | $7700.00 | Window Closed / Lapsed |