ANTENNA APPARATUS INCLUDING COMPOUND CURVE ANTENNA STRUCTURE AND FEED ARRAY

• US 20030038745A1
• Filed: 08/24/2001
• Published: 02/27/2003
• Est. Priority Date: 08/24/2001
• Status: Active Grant

• Current Assignee: BAE Systems Space & Mission Systems Incorporated (BAE Systems Plc)
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Rice, Anne, Rumsey, Ian S., Lalezari, Farzin, Kelly, P. Keith
• Granted Patent: US 6,542,118 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: H01Q 19/12 wherein the surfaces are concave H01Q19/18 takes precedence
• CPC Class Codes: H01Q 3/245 in the focal plane of a focussing device
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

An antenna apparatus that includes a beam control system and a beam collimating system having a compound curve antenna structure is provided. The compound curve antenna structure can be two-dimensional or three-dimensional. In one embodiment, the curve is parabolic and the compound curve antenna structure includes first and second parabolic reflector sections that are spaced from each other. A feed array of the beam control system is disposed therebetween at the base ends of the two parabolic reflector sections. When the compound curve antenna structure is three-dimensional, the two parabolic reflector sections are part of a body of revolution. The control system also includes memory storage that stores predetermined data related to controlling activation of each of a plurality of feed elements of the feed array. The predetermined data is based on information obtained using a reference beam with the compound curve antenna structure. In that regard, reflections and contact of EM radiation of the reference beam are monitored for a number of different scan angles. Based on the identities of the particular feed elements that are involved or receive EM radiation associated with the reference beam, determinations are made regarding the content of the predetermined data to be stored to be subsequently used in controlling activation of desired feed elements in generating a transmit beam or receiving a return beam at a desired angle of a number of scan angles.

Claims

1. An antenna apparatus, comprising:

at least a first curved reflector section and a second curved reflector section that define a compound curve antenna structure;

a feed array including a plurality of feed elements comprising at least a first feed element in communication with said first and second curved reflector sections for use in generating an antenna beam that includes at least a transmit beam; and

control system communicating with said feed array for use in controlling generation of said transmit beam, said control system including a memory storage for storing predetermined data related to controlling activation of said plurality of feed elements including at least said first feed element to provide a desired scan angle associated with said transmit beam.

2. An antenna apparatus, as claimed in claim 1, wherein:

said predetermined data relates to reference EM radiation of a reference beam striking at least one of;

a first reference curved reflector;

a second reference curved reflector; and

a reference feed array directly without first striking said first and second reference curved reflectors.

3. An antenna apparatus, as claimed in claim 2, wherein:

said first curved reflector section is said first reference curved reflector and said second curved reflector section is said second curved reflector.

4. An antenna apparatus, as claimed in claim 1, wherein:

said compound curve antenna structure has an aperture end and a base end and in which said feed array is disposed closer to said base end than to said aperture end, and in which said first curved reflector section is spaced from said second curved reflector section and with said feed array being disposed therebetween adjacent to said base end.

5. An antenna apparatus, as claimed in claim 1, wherein:

said first and second curved reflector sections are located symmetrically about a reflector axis.

6. An antenna apparatus, as claimed in claim 1, wherein:

said compound parabolic antenna structure is two-dimensional or cylindrical having two focii and in which said two focii are located adjacent to opposite ends of said feed array.

7. An antenna apparatus, as claimed in claim 1, wherein:

said first and second curved reflector sections are part of a body of revolution such that said compound curved antenna structure is three-dimensional.

8. An antenna apparatus, as claimed in claim 1, wherein:

when said desired scan angle is substantially a maximum angle of scan for said transmit beam, substantially all feed elements that are energized are located adjacent to both an end of said feed array and a end of one of said first and second curved reflector sections.

9. An antenna apparatus, as claimed in claim 1, wherein:

the number of said feed elements that are energized becomes less as said desired scan angle increases towards a maximum angle of scan.

10. An antenna apparatus, as claimed in claim 1, wherein:

said transmit beam has EM fields and the number of said EM fields that strike at least one of said first and second parabolic reflector sections for said desired scan angle is less than one-half of the total of said EM fields of said transmit beam for said desired scan angle.

11. An antenna apparatus, as claimed in claim 1, wherein:

said transmit beam is associated with a bandwidth and said bandwidth is related to the size of said compound curve antenna structure adjacent to said aperture end.

12. An antenna apparatus, as claimed in claim 1, wherein:

said desired scan angle is within a range of scan angles that includes a maximum angle of scan for said transmit beam and a greater number of said feed elements are energized to generate said transmit beam as said angle of scan moves away from said maximum angle towards said desired scan angle.

13. An antenna apparatus, as claimed in claim 1, wherein:

a number of said plurality of said feed elements are energized for use in producing said transmit beam that has a number of EM fields and in which the identities of said number of feed elements that are energized depends on at least one of;

density of said EM fields and at least one path of said EM fields associated with said desired scan angle.

14. An antenna apparatus, as claimed in claim 1, wherein:

said compound curved antenna structure is three-dimensional and has a property such that it operates in a dual-polarized mode using substantially the same number of said feed elements of said feed array as used when the antenna apparatus is a two-dimensional compound curved antenna structure for a same range of scan angles that includes said desired angle

15. An antenna apparatus, as claimed in claim 1, wherein:

said antenna beam includes a return beam and said compound curved antenna structure is three-dimensional, said return beam has a single linear polarization resulting from a dual-polarized feed provided during generation of said transmit beam.

16. An antenna apparatus, as claimed in claim 1, further including:

a plurality of said compound curved antenna structures arranged in an array.

17. An antenna apparatus, as claimed in claim 1, wherein:

said compound curved antenna structure is three-dimensional and said feed array independently controls two orthogonal polarizations in communicating with said three-dimensional compound curved antenna structure.

18. An antenna apparatus, as claimed in claim 1, wherein:

said compound curved antenna structure is three-dimensional and said predetermined data depends on a total amount of power associated with reflections using a reference return beam in a reference three-dimensional compound curved antenna structure.

19. An antenna apparatus, as claimed in claim 1, wherein:

said feed elements are spaced between about 0.5λ and

about 1λ

, while being operated using modulo 2π

phase shifters.

20. An antenna apparatus, as claimed in claim 1, wherein:

an electrical size is related to a radiating aperture and said electrical size is in the range of about 10-500 wavelengths.

21. An antenna apparatus, as claimed in claim 1, wherein:

said curve is parabolic.

23. A method, as claimed in claim 21, wherein:

said antenna beam has a scan range associated with it, wherein said scan range includes at least a first angle and a maximum angle such that a greater number of said plurality of feed elements are activated when said antenna beam is at said maximum angle than when said antenna beam is at said first angle.

24. A method, as claimed in claim 21, wherein:

said controlling step includes producing an antenna beam and said aperture end has an aperture size associated with it, said aperture size having a property that decreasing said aperture size increases bandwidth of said antenna beam.

26. A method, as claimed in claim 21, further including:

obtaining said predetermined data using a reference beam having a plurality of EM fields applied to a reference compound curve antenna structure at a number of scan angles and monitoring locations that said plurality of EM fields strike each of said reference compound curve antenna structure and a reference feed array communicating therewith.

27. A method, as claimed in claim 21, further including:

providing a number of compound curve antenna structures including said first compound curve antenna structure and with said number of compound curve antenna structures depending on a bandwidth associated with said antenna beam to be produced using said controlling step.

28. A method, as claimed in claim 21, wherein:

said first compound curve antenna structure is one of;

(i) a two-dimensional compound curve antenna structure and (ii) a three-dimensional compound curve antenna structure and in which said two-dimensional compound curve antenna structure has two focii that are located adjacent to opposite ends of said feed array.

29. A method, as claimed in claim 27, wherein:

said first compound curve antenna structure is a three-dimensional compound curve antenna structure and said step of controlling includes independently controlling two orthogonal polarizations in communicating with said first three-dimensional compound curve antenna structure.

30. A method, as claimed in claim 28, further including:

providing a plurality of three-dimensional compound curve antenna structures and having said plurality of three-dimensional compound curve antenna structures arranged according to an array.

22. A method involving control of an antenna apparatus, comprising:

providing first and second curved reflector sections and a feed array, said first and second curved reflector sections together defining a first compound curved antenna structure having a reflector axis in which said first and second parabolic reflectors are symmetrically located thereabout, said first compound curved antenna structure having an aperture end and a base end and with said feed array having a plurality of feed elements; and

controlling activation of at least a first feed element of said plurality of feed elements to generate an antenna beam that is at least one of a transmit beam and a return beam using a control system and predetermined data that is stored in memory storage related to reflections on said first and second curved reflector sections and reflections that strike said feed array directly without first contacting said first compound curved antenna structure.

25. A method, as claimed in claim 22, wherein:

said feed array has first and second ends and a center and, when said transmit beam is at said maximum angle, a substantial majority of said feed elements that are activated are located at least at one of said ends of said feed array and substantially no feed elements are activated at said center of said feed array.

31. A method, as claimed in claim 25, wherein:

said first compound curve antenna structure is three-dimensional and said monitoring step includes determining the contribution of power by each of said plurality of EM fields to a total power collected using said reference feed array in ascertaining whether power contributed by a last one of said EM fields is less than a predetermined amount of said total power.