SLIM TRIPLE BAND ANTENNA ARRAY FOR CELLULAR BASE STATIONS

• US 20090224995A1
• Filed: 10/12/2006
• Published: 09/10/2009
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Outdoor Wireless Networks LLC (CommScope Holding Company, Inc.)
• Original Assignee: Fractus SA
• Inventors: Puente, Carles, Kirchoffer, Dillon, Borja, Carmen, Teillet, Anthony, Anguera, Jaume
• Granted Patent: US 8,497,814 B2
• Time in Patent Office: Days
• US Class Current: 343/850
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 5/307 Individual or coupled radiating elements, each element being fed in an unspecified way
• CPC Class Codes: H01Q 5/42 using two or more imbricated arrays H01Q5/49 takes precedence
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H01Q 9/0414 in a stacked or folded configuration
• CPC Class Codes: H01Q 9/0435 using two feed points
• CPC Class Codes: H01Q 9/0457 electromagnetically coupled to the feed line

Abstract

The present invention refers to a triple-band antenna array for cellular base stations operating at a first frequency band and at a second frequency band within a first frequency range, and also at a third frequency band within a second frequency range. Said triple-band antenna array comprises a first set of radiating elements operating at the first frequency band, a second set of radiating elements operating at the second frequency band, a third set of radiating elements operating at both the third and the first frequency bands, and a fourth set of radiating elements operating at both the third and the second frequency bands. The radiating elements are arranged in such a way that at least some of the radiating elements of the first set are interlaced with at least some of the radiating elements of the third set, and at least some of the radiating elements of the second set are interlaced with at least some of the radiating elements of said fourth set. Further the invention relates to a slim triple-band base station for mobile/cellular services that includes in its radiating part two or more of said triple-band antenna arrays.

Claims

1. A triple-band antenna array for cellular base stations, said antenna array operating at a first frequency band, a second frequency band, and a third frequency band, said first and second frequency bands are within a first frequency range and said third frequency band is within a second frequency range, said antenna array comprising:

a first set of radiating elements operating at said first frequency band;

a second set of radiating elements operating at said second frequency band;

a third set of radiating elements operating at both of said third frequency band and said first frequency band;

a fourth set of radiating elements operating at both said third frequency band and said second frequency band;

wherein at least some radiating elements of the first set of radiating elements are interlaced with at least some radiating elements of the third set of radiating elements; and

wherein at least some radiating elements of the second set of radiating elements are interlaced with at least some radiating elements of the fourth set of radiating elements.

2. The triple-band antenna array according to claim 1, wherein said first frequency range is preferably within a range of frequencies from approximately 1700 MHz to approximately 2170 MHz, and said second frequency range is preferably within a range of frequencies from approximately 700 MHz to approximately 1000 MHz.

3. The triple-band antenna array according to claim 1, wherein:

a ratio between said second frequency band and said first frequency band is smaller than a maximum ratio selected from a group of maximum ratios comprising 1.18, 1.28, 1.38, 1.48, and 1.58;

wherein a ratio between said first frequency band and said third frequency band is larger than a minimum ratio selected from a group of minimum ratios comprising 1.3, 1.4, 1.5, 1.6 and 1.7; and

wherein a ratio between said second frequency band and said third frequency band is larger than a minimum ratio selected from a the group of minimum ratios comprising 1.3, 1.4, 1.5, 1.6 and 1.7.

4. The triple-band antenna array according to claim 1, wherein:

each of said first frequency band and said second frequency band includes two, three or more cellular or wireless services; and

wherein said cellular or wireless services included in said first frequency band and/or in said second frequency band comprise at least one of GSM1800, PCS or UMTS services.

6. The triple-band antenna array according to claim 1, wherein each radiating element from the first set of radiating elements and the second set of radiating elements is smaller than 0.5, 0.4, 0.35, or even 0.3 times a wavelength at a highest frequency of operation of each radiating element from the first and second set of radiating elements within said first frequency range.

7. The triple-band antenna array according to claim 1, wherein each radiating element from the third set of radiating elements and the fourth set of radiating elements is smaller than 0.5, 0.45, 0.4, 0.35, or even 0.3 times a wavelength at a highest frequency of operation of each radiating element from the third and fourth set of radiating elements said radiating elements within said second frequency range.

8. The triple-band antenna array according to claim 1, wherein at least some radiating elements of the triple-band antenna array are in both said third and fourth set of radiating elements.

10. The triple-band antenna array according to claim 1, wherein:

a combination of said first set of radiating elements with said third set of radiating elements provides said first frequency band;

wherein a combination of said second set of radiating elements with said fourth set of radiating elements provides said second frequency band; and

wherein a combination of said third set of radiating elements with said fourth set of radiating elements provides said third frequency band.

11. The triple-band antenna array according to claim 1, wherein the first, second third, and fourth set of radiating elements of the antenna array are substantially aligned with respect to a vertical axis.

12. The triple-band antenna array according to claim 1, wherein at least some radiating elements of the first, second, third, and fourth set of radiating elements of said antenna array are displaced off a central vertical axis of the antenna array and located on one or two sides of the antenna array.

13. The triple-band antenna array according to claim 1, wherein:

a vertical separation between two adjacent radiating elements is preferably smaller than 1, 0.9 or 0.8 times a wavelength at a highest frequency of operation of the antenna array; and

wherein a vertical spacing is constant throughout the antenna array, or different for different pairs of radiating elements.

14. The triple-band antenna array according to claim 1, wherein at least one radiating element of said first set and/or of said second set is shifted to a left side of the antenna array, and at least another radiating element of said first set and/or of said second set is shifted to a right side of the antenna array.

15. The triple-band antenna array according to claim 1, wherein:

at least some radiating elements belonging to a same set of radiating elements or to a different set of radiating elements are arranged side by side at a same vertical location but with a horizontal spacing; and

wherein said horizontal spacing between side-by-side radiating elements is smaller than 1, 0.9 or 0.8 times a wavelength at a highest frequency of operation of the antenna array.

17. The triple-band antenna array according to claim 1, wherein the third and fourth set of radiating elements are substantially on a central vertical axis of said antenna array.

18. The triple-band antenna array according to claim 1, wherein at least one pair of adjacent vertically-spaced radiating elements belongs to a same set of radiating elements.

19. The triple-band antenna array according to claim 1, wherein a number of radiating elements in each one of said first, second, third and fourth sets of radiating elements is equal the same, or different for at least two sets of radiating elements.

21. The triple-band antenna array according to claim 1 further comprising:

a ground plane; and

a height of the radiating elements included in the first set of radiating elements and/or the second set of radiating elements with respect to the ground plane of the antenna array is smaller than 0.15 or 0.08 times a wavelength at a highest frequency of operation of the radiating elements.

23. The triple-band antenna array according to claim 21, wherein said radiating elements are fed either by direct contact or through capacitive coupling at four feeding points, wherein a first and second feeding points of the four feeding points are for a given polarization, and wherein a third and fourth feeding points of the four feeding points are for another polarization substantially orthogonal to the first and second feeding points.

33. The triple-band antenna array according to claim 1, further comprising:

an adjustable electrical down-tilt mechanism to provide variable down-tilt for at least one of the frequency bands of operation of said antenna array, or to provide independent or common variable down-tilt to at least two frequency bands of operation of said antenna array.

37. The triple-band antenna array according to claim 1, wherein:

a width of said antenna array is less than 2, 1.5, 1.4, 1.3, or even 1 times a wavelength for a highest frequency of a lowest operating frequency band of said antenna array; and

wherein a thickness of said antenna array is less than 0.5, 0.4 or even 0.3 times the wavelength for the highest frequency of the lowest frequency band of said antenna array.

67. The triple-band antenna array according to claim 1, wherein at least one radiating element of said antenna array is shaped as a space-filling curve, a box-counting curve, a grid dimension curve, and/or a multilevel structure.

79. The triple-band antenna array according to claim 1, wherein the antenna array further comprises at least one of metal walls forming an enclosure around at least some radiating elements, conducting posts placed between some radiating elements, and flanges placed at edges of a ground plane.

80. The triple-band antenna array according to claim 1, wherein the antenna array further comprises at least one radiating element comprising:

a first portion adapted to operate said radiating element at a first frequency band, preferably within a range of frequencies from approximately 1700 MHz to approximately 2170 MHz;

a second portion adapted to operate said radiating element at a second frequency band, preferably within the range of frequencies from approximately 700 MHz to approximately 1000 MHz;

wherein a size of said first portion is less than half wavelength at a highest frequency of said first frequency band;

wherein a size of the second portion is less than half wavelength at a highest frequency of said second frequency band; and

wherein said first portion is mounted or stacked on top of said second portion.

81. The triple-band antenna array according to claim 80, wherein radiating elements of a stacked architecture are combined with other non-stacked radiating elements to obtain one of the operating bands of said triple-band antenna array.

82. The triple-band antenna array according to claim 80, wherein a radiating element of said third set of radiating elements or said fourth set of radiating elements further comprises at least one indentation in a second portion of the radiating element.

83. The triple-band antenna array according to claim 80, wherein a radiating element of said third set of radiating elements or said fourth set of radiating elements further comprises at least one gap in a second portion of the radiating element.

5. (canceled)

9. (canceled)

16. (canceled)

20. (canceled)

22. (canceled)

24-32. -32. (canceled)

34-36. -36. (canceled)

38. (canceled)

39. A method to capacitively couple an electrical signal between a radiating element suspended over a ground plane and a feeding transmission line arranged substantially close and parallel to said ground plane comprising the steps of:

placing a conductive elongated element vertically between said radiating element and said ground plane, wherein a top surface of said conductive elongated element is connected to the radiating element, wherein a bottom surface of said conductive elongated element is not in contact with said feeding transmission line;

providing a polygonal pad at an end of said feeding transmission line; and

creating a coupling region between the bottom surface of said conductive elongated element and said polygonal pad.

40-47. -47. (canceled)

48. A radiating element for an antenna array comprising:

a first portion adapted to operate said radiating element at a first frequency band, preferably within a range of frequencies from approximately 1700 MHz to approximately 2170 MHz;

a second portion adapted to operate said radiating element at a second frequency band, preferably within the range of frequencies from approximately 700 MHz to approximately 1000 MHz;

wherein a size of said first portion is less than half wavelength at a highest frequency of said first frequency band; and

wherein a size of the second portion is less than half wavelength at a highest frequency of said second frequency band; and

wherein said first portion is mounted or stacked on top of said second portion.

49-66. -66. (canceled)

68. A slim triple-band base station for mobile/cellular services including a radiating part, said radiating part comprising:

at least two antenna arrays, said at least two antenna arrays being radially spaced from a central axis of a structure of said slim triple-band base station;

a substantially cylindrical radome for housing said at least two antenna arrays, and being made of a dielectric material;

a central support aligned with respect to said central axis;

wherein said at least two antenna arrays are mounted on said central support at a selected distance and substantially parallel to said central axis; and

wherein each antenna array of the at least two antenna arrays is respectively placed longitudinally within an angular sector defined around said central axis.

69. The slim triple-band base station according to claim 68, wherein:

an angular spacing (A) is introduced between said at least two antenna arrays; and

wherein said radiating part further comprises a mechanical feature to steer a horizontal boresight direction of said at least two antenna arrays independently in each sector.

70-74. -74. (canceled)

75. A triple-band antenna array for cellular base stations, said antenna array operating at a first frequency band, at a second frequency band, and at a third frequency band, said antenna array comprising:

a first set of radiating elements operating at said first frequency band, each radiating element of the first set of radiating elements is smaller than half times a wavelength for a highest frequency of said first frequency band;

a second set of radiating elements operating at said second frequency band, each radiating element of the second set of radiating elements is smaller than half times a wavelength for a highest frequency of said second frequency band;

a third set of radiating elements operating at both said third frequency band and said first frequency band, each radiating element of the third set of radiating elements is smaller than half times a wavelength for a highest frequency of said third frequency band;

a fourth set of radiating elements operating at both said third frequency band and said second frequency band, each radiating element of the fourth set of radiating elements is smaller than half times a wavelength for a highest frequency of said third frequency band;

wherein at least some of the radiating elements of said first set of radiating elements are interlaced with at least some of the radiating elements of said third set of radiating elements, and wherein at least some of the radiating elements of said second set of radiating elements are interlaced with at least some of the radiating elements of said fourth set of radiating elements;

wherein at least a portion of at least one radiating element of said antenna array features a shape selected from the following group;

space-filling curve, grid-dimension curve, multilevel;

said antenna array features a width smaller than one times a longest operating wavelength for a highest frequency of a lowest frequency band and a thickness smaller than half times a wavelength for the highest frequency of the lowest frequency band;

said antenna array further comprising a set of compact phase shifters to provide variable electrical downtilt, wherein said downtilt is independent for said first, second and third frequency bands of the triple-band antenna array, and wherein a thickness of said compact phase shifters is smaller than 0.07 times the wavelength for the highest frequency of the lowest frequency band;

wherein said first and second frequency bands are within a frequency range from approximately 1700 MHz to approximately 2170 MHz and wherein said third frequency band is within a frequency range from approximately 700 MHz to approximately 1000 MHz;

wherein a ratio between said second frequency band and said first frequency band is smaller than 1.28;

wherein a ratio between said first frequency band and said third frequency band is larger than 1.5; and

wherein the ratio between said second frequency band and said third frequency band is larger 1.5.

76. A method to reduce an environmental and visual impact of a network of cellular or wireless base stations comprising:

combining at least one of a narrow width and thickness triple-band antenna array, into a substantially cylindrical radome, said cylindrical radome having a diameter of less than a maximum diameter selected from a group of maximum diameters including 1.75, 1.70, 1.65 and 1.60 times a wavelength at a highest frequency of a lowest frequency band of said antenna array;

wherein the triple band antenna array comprising;

a first set of radiating elements operating at a first frequency band;

a second set of radiating elements operating at a second frequency band;

a third set of radiating elements operating at both of a third frequency band and said first frequency band;

a fourth set of radiating elements operating at both said third frequency band and said second frequency band;

wherein at least some radiating elements of the first set of radiating elements are interlaced with at least some radiating elements of the third set of radiating elements; and

wherein at least some radiating elements of the second set of radiating elements are interlaced with at least some radiating elements of the fourth set of radiating elements.

77-78. -78. (canceled)