Cylindrical antenna coherent feed system and method

• US 6,268,828 B1
• Filed: 01/11/2000
• Issued: 07/31/2001
• Est. Priority Date: 01/11/2000
• Status: Expired due to Term

• Current Assignee: Kathrein SE
• Original Assignee: Metawave Communications Corp.
• Inventors: Martek, Gary A.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/481,267
• Time in Patent Office: 567 Days
• Field of Search: 342/373, 343/853, 343/890, 343/893
• US Class Current: 342/373
• CPC Class Codes: H01Q 19/108 Combination of a dipole with a plane reflecting surface H01Q19/106 takes precedence; strip line H01Q9/065
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 3/242 Circumferential scanning
• CPC Class Codes: H01Q 3/36 with variable phase-shifters
• CPC Class Codes: H01Q 3/40 with phasing matrix

Abstract

Systems and methods are disclosed for illuminating multiple columns of antennas to provide a desired wave front without introducing non-coherent combining. The preferred embodiment feed network provides elevation scanning for a multiple beam antenna system on a per antenna beam basis. In a preferred embodiment columns of antenna elements are divided into phase-centers having a relative phase shift introduced there between. Phase differentials are introduced into the antenna beam signals of each phase-center of antenna elements in order to provide a phase progression which steers the antenna beam a predetermined angle from the broadside. The phase differentials are independently provided for each antenna beam signal to thereby allow independent steering of each antenna beam.

Claims

1. An antenna feed system adapted to provide directional antenna beams from an antenna array having a plurality of antenna elements arranged in columns which are disposed along a curve, said system comprising:

a plurality of beam former circuits, each said beam former circuit adapted to provide a predetermined phase progression with respect to signals associated with selected ones of said columns, said predetermined phase progression being at least in part a function of said curve, each said beam former circuit also adapted to provide aperture tapering by coupling signals of outer ones of said selected ones of said columns differently than inner ones of said selected ones of said columns.

2. The system of claim 1, wherein each beam former circuit comprises:

a first phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns; and

a second phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns.

3. The system of claim 2, wherein each beam former circuit further comprises:

a phase shifter adapted to introduce a relative phase difference between signals of said first phase-center and said second phase-center to thereby provide elevational beam steering for an antenna beam of a first beam former circuit independent of an antenna beam of a second beam former circuit.

4. The system of claim 1, further comprising:

a plurality of antenna beam ports adapted to couple antenna beam signals between said antenna feed system and circuitry external to said antenna feed system, wherein at least one antenna beam port of said plurality is associated with each beam former circuit; and

a plurality of antenna column ports adapted to couple said antenna feed system to said plurality of antenna elements, wherein ones of said antenna column ports are associated with multiple ones of said beam former circuits.

5. The system of claim 1, wherein said different coupling to outer ones of said selected ones of said columns provides said signals to inner antenna elements of said outer columns.

6. The system of claim 1, wherein at least one column of said columns is coupled to at least two beam former circuits of said plurality of beam former circuits, and wherein said column aperture tapering provided by a first beam former circuit of said at least two beam former circuits is independent of beam forming by a second beam former circuit of said at least two beam former circuits.

7. The system of claim 1, wherein said beam former circuits of said plurality of beam former circuits are coupled to said selected ones of said columns without introducing non-coherent combining at the columns.

8. The system of claim 7, wherein said non-coherent combining is provided by utilizing hybrid combiners of said beam forming circuits to couple said beam forming circuits.

9. The system of claim 1, wherein a number of columns of said selected ones of said columns each beam former circuit provides a predetermined phase progress to is four.

10. The system of claim 9, wherein each said beam former circuit comprises:

a first four way splitter/combiner having an antenna beam signal port and four splitter/combiner ports associated therewith, wherein a first splitter/combiner port of said four splitter/combiner ports is coupled to an antenna element of a first column of said four columns, and wherein a second splitter/combiner port of said four splitter/combiner ports is coupled to an antenna element of a second column of said four columns;

a first hybrid combiner coupled to a third splitter/combiner port of said four splitter/combiner ports and antenna elements of said first column and a third column of said four columns; and

a second hybrid combiner coupled to a fourth splitter/combiner port of said four splitter/combiner ports and antenna elements of said second column and a fourth column of said four columns.

11. The system of claim 10, wherein each said beam former circuit further comprises:

a two way splitter/combiner having an antenna beam signal port and two splitter/combiner ports, wherein a first splitter/combiner port of said two splitter/combiner ports is coupled to the antenna beam signal port of said first four way splitter/combiner;

a second four way splitter/combiner having an antenna beam signal port and four splitter/combiner ports associated therewith, wherein a second splitter/combiner port of said two splitter/combiner ports is coupled to the antenna beam signal port of said second four way splitter/combiner, and wherein a first splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner is coupled to an antenna element of said first column of said four columns, and wherein a second splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner is coupled to an antenna element of said second column of said four columns;

a third hybrid combiner coupled to a third splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and antenna elements of said first column and said third column of said four columns; and

a fourth hybrid combiner coupled to a fourth splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and antenna elements of said second column and said fourth column of said four columns.

12. The system of claim 11, wherein each said beam former circuit further comprises:

a first phase shifter coupled between said second splitter/combiner port of said two splitter/combiner ports and the antenna beam signal port of said second four way splitter/combiner.

13. The system of claim 12, further comprising:

a controller coupled to said first phase shifter adapted to control a phase shift provided by said first phase shifter to provide elevational beam steering of an antenna beam associated with a first beam former circuit independent of a second beam former circuit.

14. The system of claim 12, wherein each said beam former circuit further comprises:

a second phase shifter coupled between said first splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and said coupled antenna element of said first column of said four columns; and

a third phase shifter coupled between said second splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and said coupled antenna element of said second column of said four columns.

15. An antenna feed system adapted to provide antenna beams from an antenna array having a plurality of antenna elements arranged in columns which are disposed along a curve, said system comprising:

a plurality of beam former circuits, each said beam former circuit adapted to provide a predetermined phase progression with respect to signals associated with selected ones of said columns, said predetermined phase progression being at least in part a function of said curve, each said beam former circuit comprising;

a first phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns;

a second phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns; and

a phase shifter adapted to introduce a relative phase difference between signals of said first phase-center and said second phase-center to thereby provide elevational beam steering for an antenna beam of a first beam former circuit independent of an antenna beam of a second beam former circuit.

16. The system of claim 15, wherein each beam former circuit comprises:

aperture tapering signal paths coupling signals of outer ones of said selected ones of said columns differently than inner ones of said selected ones of said columns.

17. The system of claim 16, wherein said aperture tapering signal paths are adapted to provide said signals to inner antenna elements of said outer columns to the exclusion of outer antenna elements of said outer columns.

18. The system of claim 16, wherein at least one column of said columns is coupled to at least two beam former circuits of said plurality of beam former circuits.

19. The system of claim 15, wherein said beam former circuits of said plurality of beam former circuits are coupled to said selected ones of said columns without introducing non-coherent combining at the columns.

20. The system of claim 19, wherein said non-coherent combining is provided by utilizing hybrid combiners of said beam forming circuits to couple said beam forming circuits.

21. The system of claim 15, wherein a number of columns of said selected ones of said columns each beam former circuit provides a predetermined phase progress to is four.

22. The system of claim 15, wherein each said beam former circuit comprises:

a first splitter/combiner having an antenna beam signal port and a plurality of splitter/combiner ports associated therewith, wherein a first splitter/combiner port of said plurality of splitter/combiner ports is coupled to an antenna element of a first column of said columns, and wherein a second splitter/combiner port of said plurality of splitter/combiner ports is coupled to an antenna element of a second column of said columns;

a first hybrid combiner coupled to a third splitter/combiner port of said plurality of splitter/combiner ports and antenna elements of said first column and a third column of said columns; and

a second hybrid combiner coupled to a fourth splitter/combiner port of said plurality of splitter/combiner ports and antenna elements of said second column and a fourth column of said columns.

23. The system of claim 22, wherein each said beam former circuit further comprises:

a second splitter/combiner having an antenna beam signal port and a plurality of splitter/combiner ports, wherein a first splitter/combiner port of said plurality of splitter/combiner ports of said second splitter/combiner is coupled to the antenna beam signal port of said first splitter/combiner;

a third splitter/combiner having an antenna beam signal port and a plurality of splitter/combiner ports associated therewith, wherein a second splitter/combiner port of said second splitter/combiner is coupled to the antenna beam signal port of said third splitter/combiner, and wherein a first splitter/combiner port of said plurality of splitter/combiner ports of said third splitter/combiner is coupled to an antenna element of said first column of said columns, and wherein a second splitter/combiner port of said plurality of splitter/combiner ports of said third splitter/combiner is coupled to an antenna element of said second column of said columns;

a third hybrid combiner coupled to a third splitter/combiner port of said plurality of splitter/combiner ports of said third splitter/combiner and antenna elements of said first column and said third column of said columns; and

a fourth hybrid combiner coupled to a fourth splitter/combiner port of said plurality of splitter/combiner ports of said third splitter/combiner and antenna elements of said second column and said fourth column of said four columns.

24. The system of claim 23, wherein each said beam former circuit further comprises:

a first phase shifter coupled between said second splitter/combiner port of said plurality of splitter/combiner ports and the antenna beam signal port of said third splitter/combiner.

25. The system of claim 24, further comprising:

a controller coupled to said first phase shifter adapted to control a phase shift provided by said first phase shifter to provide elevational beam steering of an antenna beam associated with a first beam former circuit independent of a second beam former circuit.

26. The system of claim 25, wherein each said beam former circuit further comprises:

a second phase shifter coupled between said first splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and said coupled antenna element of said first column of said columns; and

a third phase shifter coupled between said second splitter/combiner port of said four splitter/combiner ports of said second four way splitter/combiner and said coupled antenna element of said second column of said columns.

27. A method to provide directional antenna beams from an antenna array having a plurality of antenna elements arranged in columns which are disposed along a curve, said method comprising the steps of:

providing a plurality of antenna beam ports adapted to couple antenna beam signals between said antenna feed system and circuitry external to said antenna feed system;

providing a plurality of antenna column ports adapted to couple said antenna feed system to said plurality of antenna elements; and

splitting a signal provided to a first antenna beam port of said plurality of antenna beam ports to thereby provide a first plurality of split antenna beam port signals;

coupling a first split antenna beam port signal of said first plurality of split antenna beam port signals to an antenna element of a first column of said columns;

coupling a second split antenna beam port signal of said first plurality of split antenna beam port signals to an antenna element of a second column of said columns;

coupling a third split antenna beam port signal of said first plurality of split antenna beam port signals to a first hybrid combiner coupled antenna elements of said first column and a third column of said columns; and

coupling a fourth split antenna beam port signal of said first plurality of split antenna beam port signals a second hybrid combiner coupled to antenna elements of said second column and a fourth column of said columns.

28. The method of claim 27, further comprising the steps of:

providing a first group of antenna elements associated with a first antenna beam first phase-center, wherein said first plurality of split antenna beam port signals are coupled to said first antenna beam first phase-center;

providing a second group of antenna elements associated with a first antenna beam second phase-center.

29. The method of claim 28, further comprising the steps of:

splitting a signal provided to said first antenna beam port to thereby provide a second plurality of split antenna beam port signals, wherein a first split antenna beam port signal of said second plurality of split antenna beam port signals is the signal split into said first plurality of split antenna beam port signals; and

introducing a relative phase difference between said first split antenna beam port signal of said second plurality of split antenna beam port signals and a second split antenna beam port signal of said second plurality of split antenna beam port signals.

30. The method of claim 29, further comprising the step of:

selecting said relative phase difference to provide a desired amount of antenna beam elevation steering of an antenna beam associated with said first antenna beam port.

31. The method of claim 30, wherein said selecting step is independent of selecting any relative phase difference to provide a desired amount of antenna beam elevation steering of an antenna beam associated with any other antenna beam.

32. The method of claim 29, further comprising the steps of:

splitting said second split antenna beam port signal of said second plurality of split antenna beam port signals to thereby provide a third plurality of split antenna beam port signals;

coupling a first split antenna beam port signal of said third plurality of split antenna beam port signals to an antenna element of said first column of said columns;

coupling a second split antenna beam port signal of said third plurality of split antenna beam port signals to an antenna element of said second column of said columns;

coupling a third split antenna beam port signal of said third plurality of split antenna beam port signals to a third hybrid combiner coupled antenna elements of said first column and said third column of said columns; and

coupling a fourth split antenna beam port signal of said second plurality of split antenna beam port signals a fourth hybrid combiner coupled to antenna elements of said second column and said fourth column of said columns.

33. An antenna feed system adapted to provide a directional antenna beam from an antenna array having a plurality of antenna elements arranged in columns which are disposed in a circle, said system comprising:

a first beam former circuit adapted to provide a predetermined phase progression with respect to signals associated with selected ones of said columns disposed to provide at least two broadside edge columns, said first beam former circuit also adapted to provide aperture tapering by energizing only inner antenna elements of said broadside edge columns, said first beam former circuit comprising;

a first phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns;

a second phase-center of antenna elements of said columns having said predetermined phase progression with respect to signals associated with said selected ones of said columns; and

a phase shifter adapted to introduce a relative phase difference between signals of said first phase-center and said second phase-center to thereby provide elevational beam steering for an antenna beam of said first beam former circuit independent of any other antenna beam.

34. The system of claim 33, wherein said circle of columns includes twelve columns and wherein a number of said selected ones of said columns provided said predetermined phase progression by said first beam former circuit is four.

35. The system of claim 34, wherein said columns include four antenna elements each.

36. The system of claim 35, wherein four antenna elements of said four columns coupled to said first beam former circuit are not coupled to said first beam former circuit.

37. The system of claim 33, further comprising:

a plurality of beam former circuits each configured to provide connections substantially the same as said first beam former circuit although coupled to differing ones of said columns.

38. The system of claim 37, wherein each beam former of said plurality of beam former circuits and said first beam former circuit are coupled to at least two shared columns of said columns, wherein shared columns are coupled to at least two beam former circuits of said plurality of beam former circuits and said first beam former circuit.