Single and dual-band patch/helix antenna arrays

• US 6,720,935 B2
• Filed: 07/12/2002
• Issued: 04/13/2004
• Est. Priority Date: 07/12/2002
• Status: Active Grant

• Current Assignee: Mitre Corporation
• Original Assignee: Mitre Corporation
• Inventors: Lamensdorf, David, Smolinski, Michael
• Primary Examiner(s): CHEN, SHIH CHAO
• Application Number:
  US10/194,027
• Publication Number:
  US 20040008153A1
• Time in Patent Office: 641 Days
• Field of Search: 343/700.MS, 343/702, 343/725, 343/830, 343/846, 343/895, 343/850, 343/853
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

Single and dual frequency band spatial null steering antenna arrays are disclosed, comprised of primary resonant quadrifilar helix antennas and auxiliary resonant patch antennas, which comprise stacked patches in the dual-band embodiments. Several feed networks are described for producing, preferably, circularly polarized radiation in satellite frequency bands (e.g., L1 and L2) with pattern nulls steerable to desired elevation angles. Various top and bottom-fed quadrifilar helix antennas configurations are also described.

Claims

1. A spatial null steering antenna array, comprising:

a resonant quadrifilar helix antenna having a plurality of feed locations;

means for feeding the plurality of feed locations in phase quadrature to produce circular polarization in a resonant frequency band;

a ground plate coaxially aligned with and vertically displaced above the quadrifilar helix antenna;

a dielectric layer and an auxiliary patch resonant in that frequency band coaxially aligned and vertically stacked on the ground plate, the auxiliary patch having one or more feed pins;

means for feeding the one or more feed pins of the auxiliary patch in order to produce a combined circularly polarized radiation pattern minimum at selected elevation angles in the frequency band.

2. The spatial null steering antenna array of claim 1, wherein the resonant frequency band is in a satellite frequency range.

3. The spatial null steering antenna array of claim 1, wherein the resonant frequency band is a L1 band.

4. The spatial null steering antenna array of claim 1, wherein the resonant frequency band is a L2 band.

5. The spatial null steering antenna array of claim 1, further comprising a protective radome covering the quadrifilar helix antenna and auxiliary patch.

6. The spatial null steering antenna array of claim 1, further comprising:

means for supporting the helical structure of the quadrifilar helix antenna.

7. The spatial null steering antenna array of claim 1, wherein the resonant quadrifilar helix antenna further comprises:

four radiating elements for radiating RHCP arranged helically with a left twist defining a cylinder of constant radius, each radiating element having an electrically open end near the ground plate and another end having an electrically conductive feed location; and

a ground plane coaxially positioned below the four radiating elements.

8. The spatial null steering antenna array of claim 7, wherein the ground plane is substantially circular and has a diameter equal to or greater than one third of the wavelength in free space of the signals being fed to the feed locations.

9. The spatial null steering antenna array of claim 7, wherein the means for feeding the quadrifilar helix antenna further comprises:

a 180°

hybrid for providing from an input signal first and second output signals that differ from each other by 180°

;

a first 90°

hybrid having an input arm for accepting the first output signal from the 180°

hybrid and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein the third and fourth output signals differ from one another by 90°

;

a second 90°

hybrid having an input arm for accepting said second output signal from the 180°

hybrid and further having a third output arm for providing a fifth output signal and a fourth output arm for providing a sixth output signal, wherein said fifth and sixth output signals differ from one another by 90°

; and

wherein the third, fourth, fifth and sixth output signals are provided to the feed locations of the four radiating elements.

10. The spatial null steering antenna array of claim 7, wherein the means for feeding the quadrifilar helix antenna further comprises:

a 90°

hybrid for providing from an input signal first and second output signals that differ from each other by 90°

;

a first 180°

hybrid having an input arm for accepting the first output signal from the 90°

hybrid and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein the third and fourth output signals differ from one another by 180°

;

a second 180°

hybrid having an input arm for accepting said second output signal from the 90°

hybrid and further having a third output arm for providing a fifth output signal and a fourth output arm for providing a sixth output signal, wherein said fifth and sixth output signals differ from one another by 180°

; and

wherein the third, fourth, fifth and sixth output signals are provided to the feed locations of the four radiating elements.

11. The spatial null steering antenna array of claim 1, wherein the resonant quadrifilar helix antenna has a top and bottom and further comprises:

four radiating elements for radiating RHCP arranged helically with a right twist defining a cylinder of constant radius, each radiating element having one end with an electrically conductive feed location at the top of the helix antenna, and another electrically open end at the bottom of the helix antenna.

12. The spatial null steering antenna array of claim 11, wherein the means for feeding the quadrifilar helix antenna further comprises:

a 180°

hybrid for providing from an input signal first and second output signals that differ from each other by 180°

;

a first 90°

hybrid having an input arm for accepting the first output signal from the 180°

hybrid and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein the third and fourth output signals differ from one another by 90°

;

a second 90°

hybrid having an input arm for accepting said second output signal from the 180°

hybrid and further having a third output arm for providing a fifth output'"'"'signal and a fourth output arm for providing a sixth output signal, wherein the fifth and sixth output signals differ from one another by 90°

; and

wherein the third, fourth, fifth and sixth output signals are provided to the feed locations of the four radiating elements through a conduit extending along the axis of and above the quadrifilar helix antenna through which auxiliary patch feed signals are also carried.

13. The spatial null steering antenna array of claim 1, further comprising:

means for supporting the ground plate relative to the quadrifilar helix antenna.

14. The spatial null steering antenna array of claim 13, wherein the support means further comprises:

a conduit extending along the axis of and above the quadrifilar helix antenna through which auxiliary patch feed signals are carried.

15. The spatial null steering antenna array of claim 13, further comprising:

a conduit mechanism extending along the axis within and above the quadrifilar helix antenna, through which quadrifilar helix antenna feed signals are also carried.

16. The spatial null steering antenna array of claims 7 or 11, wherein the four radiating elements are further comprised of strips of electrically conductive material printed on a dielectric support.

17. The spatial null steering antenna array of claims 7 or 11, wherein each radiating element has a length less than or equal to the wavelength in free space of the signals being fed to the feed locations.

18. The spatial null steering antenna array of claims 7 or 11, wherein each radiating element completes at most one helical turn.

19. The spatial null steering antenna array of claim 1, wherein the auxiliary patch has substantially square or round resonant dimensions.

20. The spatial null steering antenna array of claim 1, wherein the auxiliary patch feed means further comprises:

a weighting feed network to adaptively or predictively steer the direction of the spatial null in the antenna pattern.

21. The spatial null steering antenna array of claim 1, wherein the auxiliary patch feed means further comprises:

a first 90°

hybrid having a first output arm for providing from an input signal a first output signal and a second output arm for providing a second output signal, wherein the first and second output signals differ from one another by 90°

;

a set of feed wires electrically connected to the first and second output arms and carried through a conduit extending along the axis of and above the quadrifilar helix antenna; and

wherein the one or more auxiliary patch feed pins extend through holes in the ground plate and dielectric layer for electrical connection to the set of feed wires.

22. A dual-band spatial null steering antenna array, comprising:

a dual-band quadrifilar helix antenna resonant in a first frequency band and a second frequency band having a plurality of feed locations;

means for feeding the plurality of feed locations of the dual-band quadrifilar helix antenna to produce circular polarization in the first frequency band and the second frequency band;

a ground plate coaxially aligned with and vertically displaced above the dual-band quadrifilar helix antenna;

a first auxiliary patch resonant in the first frequency band and a second auxiliary patch resonant in the second frequency band coaxially aligned and vertically stacked on a dielectric substrate layer on top of the ground plate;

means for feeding the first patch and the second patch to produce combined circularly polarization pattern minima at selected elevation angles in the first and the second frequency bands.

23. The dual-band spatial null steering antenna array of claim 22, wherein the first frequency band and second frequency band are in a satellite frequency range.

24. The dual-band spatial null steering antenna array of claim 22, wherein the first frequency band is a L2 band.

25. The dual-band spatial null steering antenna array of claim 22, wherein the second frequency band is a L1 band.

26. The dual-band spatial null steering antenna array of claim 22, further comprising a protective radome covering the dual-band quadrifilar helix antenna and the stacked auxiliary patches.

27. The dual-band spatial null steering antenna array of claim 22, further comprising means for supporting the helical structure of the dual-band quadrifilar helix antenna.

28. The dual-band spatial null steering antenna array of claim 22, further comprising means for supporting the position of the ground plate and stacked patches relative to the dual-band quadrifilar helix antenna.

29. The dual-band spatial null steering antenna array of claim 28, wherein the support means further comprises:

a conduit mechanism extending coaxially within and above the dual-band quadrifilar helix antenna through which the means for feeding the first patch and the second patch are carried.

30. The dual-band spatial null steering antenna array of claim 28, further comprising:

a conduit mechanism extending coaxially within and above the quadrifilar helix antenna, through which quadrifilar helix antenna feed signals are also carried.

31. The dual-band spatial null steering antenna array of claim 22, further comprising means for supporting the helical structure of the dual-band quadrifilar helix antenna.

32. The dual-band spatial null steering antenna array of claim 22, wherein the ground plane is a substantially circular metal plate.

33. The dual-band spatial null steering antenna array of claim 22, wherein the means for feeding the first patch and the second patch further comprises:

a weighting network to adaptively or predictively steer the direction of the spatial null in the array pattern.

34. The dual-band spatial null steering antenna array of claim 22, wherein the dual-band quadrifilar helix antenna further comprises:

four radiating elements for radiating RHCP arranged helically with a left twist defining a cylinder of constant radius, each radiating element having an upper portion and a lower portion and a gap there between, each upper portion having an open end, and each lower portion having one of the plurality of feed locations for receiving feed signals in phase quadrature;

four traps, one corresponding trap each disposed in the gap and electrically connected to the upper portion and lower portion of a corresponding one of the four radiating elements equidistant from the corresponding open end, the traps configured to have a first impedance in the first frequency band, and a second impedance greater than the first impedance in the second frequency band; and

a ground plane coaxially positioned below the four radiating elements.

35. The dual-band spatial null steering antenna array of claim 34, wherein the four radiating elements are further comprised of strips of electrically conductive material printed on a dielectric support.

36. The dual-band spatial null steering antenna array of claim 34, wherein the ground plane is substantially circular and has a diameter equal to or greater than one third of the wavelength in free space of the feed signals being fed to the feed locations.

37. The dual-band spatial null steering antenna array of claim 34, wherein the means for feeding the dual-band quadrifilar helix antenna further comprises:

a 180°

hybrid for providing from an input signal first and second output signals that differ from each other by 180°

;

a first 90°

hybrid having an input arm for accepting said first output signal from said 180°

hybrid and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

;

a second 90°

hybrid having an input arm for accepting said second output signal from said 180°

hybrid and further having a third output arm for providing a fifth output signal and a fourth output arm for providing a sixth output signal, wherein said fifth and sixth output signals differ from one another by 90°

; and

wherein the third, fourth, fifth and sixth output signals are provided to the feed locations of the four radiating elements.

38. The dual-band spatial null steering antenna array of claim 34, wherein the length of each of the four radiating elements is less than or equal to the wavelength in free space of the signals being fed to the feed locations.

39. The dual-band spatial null steering antenna array of claim 34, wherein each radiating element completes at most one helical turn.

40. The dual-band spatial null steering antenna array of claim 34, wherein the traps are comprised of printed circuit components.

41. The dual-band spatial null steering antenna array of claim 22, wherein the dual-band quadrifilar helix antenna has a top and a bottom and further comprises:

four radiating elements for radiating RHCP arranged helically with a right twist defining a cylinder of constant radius, each radiating element having an upper portion and a lower portion and a gap there between, each upper portion having one of the plurality of feed locations for receiving feed signals in phase quadrature at the top of the helix, and each lower portion having an electrically open end at the bottom of the helix; and

four traps, one corresponding trap each disposed in the gap and electrically connected to the upper portion and lower portion of a corresponding one of the four radiating elements equidistant from the corresponding open end, the traps configured to have a first impedance in the first frequency band, and a second impedance greater than the first impedance in the second frequency band.

42. The dual-band spatial null steering antenna array of claim 41, wherein the means for feeding the quadrifilar helix antenna further comprises:

a 180°

hybrid for providing from an input signal first and second output signals that differ from each other by 180°

;

a first 90°

hybrid having an input arm for accepting said first output signal from said 180°

hybrid and further having a first output arm for providing a third output signal and a second output arm for providing a fourth output signal, wherein said third and fourth output signals differ from one another by 90°

;

a second 90°

hybrid having an input arm for accepting said second output signal from said 180°

hybrid and further having a third output arm for providing a fifth output signal and a fourth output arm for providing a sixth output signal, wherein said fifth and sixth output signals differ from one another by 90°

; and

wherein the third, fourth, fifth and sixth output signals are provided to the feed locations of the four radiating elements through a conduit mechanism extending coaxially within and above the dual-band quadrifilar helix antenna.

43. The dual-band spatial null steering antenna array of claim 41, wherein the four radiating elements are further comprised of strips of electrically conductive material printed on a dielectric support.

44. The dual-band spatial null steering antenna array of claim 41, wherein the length of each of the four radiating elements is less than or equal to the wavelength in free space of the signals being fed to the feed locations.

45. The dual-band spatial null steering antenna array of claim 41, wherein each radiating element completes at most one helical turn.

46. The dual-band spatial null steering antenna array of claim 41, wherein the traps are comprised of printed circuit components.

47. The dual-band spatial null steering antenna array of claim 22, wherein

the first and second auxiliary patches have substantially square dimensions;

and

the first auxiliary patch has a greater surface area than the second auxiliary patch and is stacked below the second auxiliary patch.

48. The dual-band spatial null steering antenna array of claim 22, wherein

the first and second auxiliary patches have substantially round dimensions;

and

the first auxiliary patch has a greater surface area than the second auxiliary patch and is stacked below the second auxiliary patch.

49. The dual-band spatial null steering antenna of claim 22, wherein the means for feeding the first patch and the second patch further comprises:

a first set of one or more feed pins electrically connected to the first auxiliary patch and extending through the ground plate and dielectric layer, and a second set of one or more feed pins electrically connected to the second auxiliary patch and extending through the ground plate, dielectric layer and first auxiliary patch; and

a feed network electrically connected to the first and second sets that feeds feed signals resulting in circularly polarized radiation.

50. The dual-band spatial null steering antenna array of claim 49, wherein

each set of feed pins is a corresponding pair of feed pins;

and

the feed network is further comprised of one or more 90°

hybrids.

51. The dual-band spatial null steering antenna array of claim 22, wherein the means for feeding the first patch and second patch further comprises electromagnetic coupling means.