Deployable phased array of reflectors and method of operation

• US 6,268,835 B1
• Filed: 01/07/2000
• Issued: 07/31/2001
• Est. Priority Date: 01/07/2000
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Barlevy, Alon S., Hamada, Shinobu J., Gilger, L. Dwight, Toland, Brent T., Chan, Ronald Y.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): NGUYEN, HOANG V
• Application Number:
  US09/480,699
• Time in Patent Office: 571 Days
• Field of Search: H01/Q 2.100, H01/Q 1.914, 343/781.P, 343/776, 343/844, 343/853, 343/915, 343/DIG.2, 343/781.R, 343/840, 343/775, 342/74, 342/368
• US Class Current: 343/781.00P
• CPC Class Codes: H01Q 1/08 Means for collapsing antennas or parts thereof collapsible loop antennas H01Q7/02; means for collapsing H-antennas or Yagi antennas H01Q19/04
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 15/168 Mesh reflectors mounted on a non-collapsible frame
• CPC Class Codes: H01Q 19/17 the primary radiating source comprising two or more radiating elements H01Q19/15, H01Q25/00 take precedence
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/2658 Phased-array fed focussing structure
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence
• CPC Class Codes: Y10S 343/02 Satellite-mounted antenna

Abstract

A deployable phased-array-of-reflectors antenna includes individual reflectors and feed arrays. Each feed array is disposed above a corresponding individual reflector. The individual reflector antennas are preferably disposed adjacent to one another (e.g., on a hexagonal lattice) to form a phased array antenna using the individual reflectors antennas as elements. Phase and amplitude control electronics are coupled to each reflector antenna to provide steering for the signal energy coupled between the reflectors and the feed arrays. Switching electronics are coupled to the feed arrays and selectively activate and deactivate beam forming clusters of feeds in the feed arrays. A method for generating a steerable antenna pattern couples signal energy through a beamforming section to form steered signal energy. Next, the method couples the steered signal energy between a phased array of reflector antennas. The method selectively activates a first feed cluster for a first reflector, a second feed cluster for a second reflector, and so on, until feed clusters are activated in all of the reflectors in the array. The method then couples the steered signal energy between the first and second feed clusters. The method subsequently activates and deactivates the feed clusters to reduce the impact of grating lobes in the total antenna pattern, or when a particular cluster attenuation has been reached.

Claims

1. A phased-array-of-reflectors antenna comprising:

plurality of reflector antennas pointed toward a common direction each comprising a reflector having a rim defining a substantially circular shape and each comprising a feed array disposed above the individual reflector;

each reflector antenna being disposed adjacent to at least one other reflector antenna in the plurality of reflector antennas to form a phased array antenna using the plurality of reflector antennas as phased array antenna elements so that the signal energy from the plurality of reflector antennas combines to form a beam.

2. A phased reflector array according to claim 1, wherein the plurality of reflectors comprises four or more individual reflectors arranged substantially on a periodic reflector lattice.

3. A phased reflector array according to claim 2, wherein at least one of the feed arrays comprises four or more individual feeds arranged substantially on a periodic feed lattice.

4. A phased reflector array antenna according to claim 3, wherein the periodic feed lattice is a periodic hexagonal feed lattice.

5. A phased reflector array according to claim 2, wherein at least one of the feed arrays comprises four or more individual feeds arranged substantially on a aperiodic feed lattice.

6. A phased reflector array antenna according to claim 2, wherein each feed array is disposed at a corresponding individual reflector focal point.

7. A phased reflector array antenna according to claim 2, wherein the periodic reflector lattice is a periodic hexagonal reflector lattice.

8. A phased reflector array according to claim 1, wherein the plurality of reflector antennas comprises four or more individual reflectors arranged on an aperiodic lattice.

9. A phased reflector array antenna according to claim 1, further comprising:

phase and amplitude control means coupled to each individual reflector for steering the individual reflectors.

10. A phased reflector array antenna according to claim 1, further comprising switching means coupled to the feed arrays for selectively activating and deactivating feeds in the feed arrays.

11. A phased reflector array antenna according to claim 10, wherein the switching means is a switch matrix for selectively activating and deactivating at least first and second element clusters of feeds that form a beam.

12. A phased reflector array antenna according to claim 11, wherein the switch matrix deactivates the first element cluster and activates the second element cluster when the beam steers within a predetermined angular range of the first element cluster.

13. A phased reflector array antenna according to claim 12, wherein the predetermined angular range is selected according to a minimum acceptable grating lobe specification.

14. An antenna pattern for a phased reflector array antenna, the antenna pattern comprising a reflector array pattern in product with array-fed reflector patterns, the reflector array pattern generated by a lattice of four or more reflector antennas, the pattern from each of said reflector antennas comprising a substantially circular shape, and the array-fed reflector patterns generated by selectively actuable array feeds above the reflector antennas.

15. An antenna pattern according to claim 14, wherein the reflector array pattern is a reflector array pattern corresponding to a lattice of reflector antennas disposed adjacent to one another.

16. An antenna pattern according to claim 14, wherein at lest one of the array-fed reflector patterns is an array feed pattern corresponding to an array feed comprising individual feeds arranged in a lattice.

17. An antenna pattern according to claim 14, wherein the reflector array pattern is a reflector array pattern corresponding to a substantially hexagonal lattice of reflector antennas.

18. An antenna pattern according to claim 14, wherein at least one of the array-fed reflector patterns is an array-fed reflector pattern corresponding to a feed array illuminating a reflector and comprising individual feeds arranged in a hexagonal lattice.

19. A method for generating a steerable antenna pattern, the method comprising:

coupling signal energy through a beamforming section to form steered signal energy;

selectively activating a first feed cluster for a beam and a second feed cluster for the beam, the first feed cluster selected from feed elements in a first feed array for a first reflector antenna, the second feed cluster selected from feed elements in a second feed array for a second reflector antenna, the first and second reflector antennas being pointed toward a common direction and being adjacently disposed to form a phased array reflector antenna using the first and second reflector antennas as phased array antenna elements so that the signal energy from the first and second feed clusters combines to form said beam; and

coupling the steered signal energy between the first and second reflector antennas and the first and second feed clusters.

20. A method according to claim 19, wherein the step of coupling steered signal energy comprises coupling signal energy to the first and second reflector antennas and to the first and second feed clusters to transmit the signal energy.

21. A method according to claim 19, wherein the step of coupling steered signal energy comprises coupling signal energy from the first and second reflector antenna and from the first and second feed clusters to receive the signal energy.

22. A method according to claim 19, wherein the step of coupling steered signal energy further comprises first coupling the steered signal energy between the first and second reflector antennas arranged on a substantially hexagonal reflector array lattice.

23. A method according to claim 19, wherein the step of coupling steered signal energy between the first and second feed clusters further comprises coupling the steered signal energy between first and second feed clusters arranged on a substantially hexagonal lattice.

24. A method according to claim 19, further comprising the step of steering the signal energy to a predetermined angle using the beamforming section.

25. A method according to claim 19, further comprising the step of selectively deactivating the first feed cluster and activating a third feed cluster for a second beam and selectively deactivating the second feed cluster and activating a fourth feed cluster for the second beam, the third feed cluster selected from feed elements in the first feed array, the fourth feed cluster selected from feed elements in the second feed array.

26. A method according to claim 25, wherein the step of deactivating the first feed cluster and the step of deactivating the second feed cluster occur when the steered signal energy experiences a predetermined attenuation.

27. A method according to claim 26, wherein the step of deactivating the first feed cluster and the step of deactivating the second feed cluster occur when a predetermined minimum acceptable grating lobe specification is exceeded.

28. A phased reflector array antenna comprising:

a plurality of reflector antennas pointed toward a common direction each comprising a reflector and a feed array, the feed array disposed above the reflector, the reflector comprising a reflector surface pulled into shape by a plurality of drop ties coupled to a shaping surface, and wherein each reflector antenna is disposed adjacent to at least one other reflector antenna and shares at least one of said drop ties with said one other reflector antenna in the plurality of reflector antennas to form a phased array antenna using the plurality of reflector antennas as phased array antenna elements to form a communication beam.

29. The phased reflector array antenna of claim 28, wherein the drop ties may be spring loaded drop ties.

30. The phased reflector array antenna of claim 28, wherein the individual reflector antennas have a hexagonal periphery, and wherein a portion of the hexagonal periphery is shared with an adjacent reflector antenna in the plurality of reflector antennas.

31. The phased reflector array antenna of claim 30, further comprising rigid support posts located at corner points of the hexagonal periphery.

32. The phased reflector array antenna of claim 30, further comprising a hexagonal support web around a hexagonal periphery of the shaping surface.

33. The phased reflector array antenna of claim 30, further comprising a hexagonal support web around a hexagonal periphery of the reflector surface.

34. The phased reflector array antenna of claim 30 further comprising a hexagonal support web around a hexagonal periphery of the feed support plane surface.

35. The phased reflector array antenna of claim 28, wherein the reflector surface is an elastic RF material reflector surface.

36. The phased reflector array antenna of claim 28, wherein the reflector surface comprises a plurality of flat facets, and wherein the drop ties are secured at vertex points of the flat facets.

37. The phased reflector array antenna of claim 36, wherein the flat facets are triangular flat facets.

38. The phased reflector array antenna of claim 28, wherein the shaping surface comprises a plurality of flat facets, and wherein the drop ties are secured at vertex points of the flat facets.