Miniature antenna having a volumetric structure

• US 7,504,997 B2
• Filed: 08/12/2005
• Issued: 03/17/2009
• Est. Priority Date: 02/19/2003
• Status: Expired due to Term

• Current Assignee: HTC Corporation
• Original Assignee: Fractus SA
• Inventors: Anguera-Pros, Jaume, Ortigosa-Vallejo, Juan Ignacio, Soler-Castany, Jordi, Baliarda, Carles Puente
• Primary Examiner(s): MANCUSO, HUEDUNG XUAN CAO
• Application Number:
  US11/202,881
• Publication Number:
  US 20060082505A1
• Time in Patent Office: 1,313 Days
• Field of Search: 343/700.MS, 343/702, 343/797, 343/853
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 11/14 with parts bent, folded, shaped or screened or with phasing impedances, to obtain desired phase relation of radiation from selected sections of the antenna or to obtain desired polarisation effect H01Q11/20 takes precedence
• CPC Class Codes: H01Q 11/16 in which the selected sections are collinear
• CPC Class Codes: H01Q 11/18 in which the selected sections are parallelly spaced
• CPC Class Codes: H01Q 15/0093 having a fractal shape
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

A miniature antenna includes a radiating arm that defines a grid dimension curve. In one embodiment, the radiating arm includes a planar portion and at least one extruded portion. The planar portion of the radiating arm defines the grid dimension curve. The extruded portion of the radiating arm extends from the planar portion of the radiating arm to define a three-dimensional structure. In one embodiment, the miniature antenna includes a first radiating arm that defines a first grid dimension curve within a first plane and a second radiating arm that defines a second grid dimension curve within a second plane. In one embodiment, the miniature antenna includes a radiating arm that forms a non-planar structure.

Claims

1. A miniature antenna, comprising:

a radiating arm that defines a grid dimension curve within a plane of the antenna;

the radiating arm having a planar portion that defines the grid dimension curve;

the radiating arm farther having at least one extruded portion extending from the planar portion to define a three-dimensional structure;

wherein the physical dimensions of the antenna are smaller than one-fifteenth of a free-space operating wavelength of the antenna; and

wherein the grid dimension curve defines a space-filling curve;

wherein the space-filling curve comprises at least ten segments;

wherein each of the at least ten segments forms an angle with an adjacent segment of the at least ten segments and is shorter than one-tenth of the free-space operating wavelength.

2. The miniature antenna of claim 1, wherein the radiating arm comprises a feeding point to couple the antenna with a transmission medium.

3. The miniature antenna of claim 2, wherein the feeding point is located on the planar portion of the radiating arm.

4. The miniature antenna of claim 2, wherein the feeding point is located on the extruded portion of the radiating arm.

5. The miniature antenna of claim 1, wherein the radiating arm is coupled to a ground potential.

6. The miniature antenna of claim 1, wherein the extruded portion is located along a section of the planar portion having a high current density relative to other sections of the planar portion.

7. The miniature antenna of claim 1, wherein the grid dimension curve defines a rectangular periphery.

8. The miniature antenna of claim 1, wherein the planar portion of the radiating arm is extruded in a direction perpendicular to the plane of the grid dimension curve to form the extruded portion of the radiating arm, and wherein the extruded portion forms a three-dimensional representation of the grid dimensional curve.

9. The miniature antenna of claim 8, wherein the miniature antenna is separated by a pre-defined distance from a ground plane.

10. The miniature antenna of claim 9, wherein the planar portion of the radiating arm is perpendicular to the ground plane.

11. The miniature antenna of claim 9, wherein the plane of the grid dimension curve forms an angle with the ground plane.

12. The miniature antenna of claim 1, wherein the grid dimension curve has a conductor length, and wherein the conductor length of the grid dimension curve is pre-selected to tune the frequency band of the antenna.

13. The miniature antenna of claim 1, wherein a grid dimension value of the grid dimension curve is pre-selected to tune the frequency band of the antenna.

14. The miniature antenna of claim 1, further comprising a top-loading portion coupled to the radiating arm.

15. The miniature antenna of claim 14, wherein the top-loading portion lies in a second plane that is perpendicular to the plane of the grid dimension curve.

16. The miniature antenna of claim 15, wherein the grid dimension curve comprises a first end and a second end, the first end being a feeding point of the antenna and the second end being coupled to the top-loading portion.

17. The miniature antenna of claim 1, further comprising:

a second radiating arm that defines a second grid dimension curve within a second plane of the antenna;

the second radiating arm having a planar portion that defines the second grid dimension curve;

the second radiating arm having at least one extruded portion extending from the planar portion to define a three-dimensional structure.

18. The miniature antenna of claim 17, wherein:

the radiating arm is an active radiating arm that comprises a feeding point to coupled the antenna with a transmission medium;

the second radiating arm is a parasitic radiating arm that is coupled to a ground potential; and

the radiating arm is electromagnetically coupled to the second radiating arm.

19. The miniature antenna of claim 18, wherein a distance between the radiating arm and the second radiating arm is pre-selected to determine the degree of electromagnetic coupling between the radiating arm and the second radiating arm.

20. The miniature antenna of claim 18, wherein the plane of the grid dimension curve and the second plane of the second grid dimension curve are parallel.

21. The miniature antenna of claim 18, wherein the grid dimension curve defined by the radiating arm and the second grid dimension curve defined by the second radiating arm lie in the same plane.

22. The miniature antenna of claim 17, further comprising:

a first top-loading portion coupled to the radiating arm;

and a second top-loading portion coupled to the second radiating arm.

23. The miniature antenna of claim 22, wherein the first top-loading portion lies in a third plane and the second top-loading portion lies in a fourth plane, and wherein the third and fourth planes are perpendicular to the plane of the grid dimension curve.

24. The miniature antenna of claim 23, wherein the third plane is parallel with the fourth plane.

25. The miniature antenna of claim 23, wherein the first top-loading portion is electromagnetically coupled to the second top-loading portion.

26. The miniature antenna of claim 22, wherein the first and second top-loading portions include planar conductors.

27. The miniature antenna of claim 17, wherein the first and second top-loading portions define grid dimension curves.

28. The miniature antenna of claim 17, further comprising:

a common top-loading portion coupled to the radiating arm and the second radiating arm.

29. The miniature antenna of claim 17, further comprising a common feeding portion coupled to the radiating arm and the second radiating arm.

30. The miniature antenna of claim 29, wherein the common feeding portion comprises a feeding point to couple the antenna to a transmission medium.

31. The miniature antenna of claim 1, wherein the radiating arm is one of a plurality of radiating arms, each of the plurality of radiating arms having a planar portion that defines a grid dimension curve and at least one extruded portion extending from the planar portion to define a three-dimensional structure.

32. The miniature antenna of claim 31, wherein the antenna comprises four radiating arms, and further comprising:

a common feeding portion coupled to a first end of each of the radiating arms; and

a common top-loading portion coupled to a second end of each of the radiating arms;

wherein the common feeding portion comprises a feeding point to couple the antenna to a transmission medium.

33. The miniature antenna of claim 1, wherein:

the grid dimension curve has a grid dimension (D_g) greater than one;

$D_g=\frac{\log <br><br>\left(N<br><br><br><br>2\right)-\log <br><br>\left(N<br><br><br><br>1\right)}{\log <br><br>\left(L<br><br><br><br>2\right)-\log <br><br>\left(L<br><br><br><br>1\right)};<br><br>$

L1 is a length of square cells of a first grid positioned over the grid dimension curve such that the first grid completely covers the grid dimension curve;

N1 is the number of the square cells of the first grid that enclose at least a portion of the grid dimension curve;

L2 is a length of square cells of a second grid positioned over the grid dimension curve such that the second grid completely covers the grid dimension curve;

N2 is the number of the square cells of the second grid that enclose at least a portion of the grid dimension curve;

the first grid and the second grid are each positioned such that no entire row or column on a perimeter of either of the grids fails to enclose at least a portion of the grid dimension curve;

the first grid comprises twenty-five cells;

the second grid has four times the number of cells as the first grid; and

L2 is equal to 0.5 L1.

34. The miniature antenna of claim 33 wherein the grid dimension curve has a grid dimension greater than 1.2.

35. The miniature antenna of claim 33 wherein the grid dimension curve has a grid dimension greater than 1.5.

36. The miniature antenna of claim 33 wherein the grid dimension curve has a grid dimension greater than 1.65.

37. The miniature antenna of claim 33 wherein the grid dimension curve has a grid dimension greater than 1.9.

38. A miniature antenna, comprising:

a first radiating arm that defines a first grid dimension curve within a first plane; and

a second radiating arm that defines a second grid dimension curve within a second plane;

wherein the physical dimensions of the antenna are smaller than one-fifteenth of a free-space operating wavelength of the antenna and

wherein the each of the first grid dimension curve and the second grid dimension curve defines a space-filling curve;

wherein the space-filling curve comprises at least ten segments

wherein each of the at least ten segments forms an angle with an adjacent segment of the at least ten segments and is shorter than one-tenth of the free-space operating wavelength.

39. The miniature antenna of claim 38, wherein at least one of the radiating arms comprises a feeding point to coupled the antenna to a transmission medium.

40. The miniature antenna of claim 38, wherein:

the first radiating arm comprises a first dielectric substrate and the first grid dimension curve is defined by a first conductor attached to the first dielectric substrate; and

the second radiating arm comprises a second dielectric substrate and the second grid dimension curve is defined by a second conductor attached to the second dielectric substrate.

41. The miniature antenna of claim 39, wherein the first radiating arm is an active radiating arm that comprises the feeding point and the second radiating arm is a parasitic radiating arm that is coupled to a ground potential.

42. The miniature antenna of claim 41, wherein the parasitic radiating arm is a solid conductor the defines a slot, and wherein the slot in the parasitic radiating arm defines the second grid dimension curve.

43. The miniature antenna of claim 41, wherein the first radiating arm is electromagnetically coupled to the second radiating arm.

44. The miniature antenna of claim 43, wherein the first radiating arm is separated from the second radiating arm by a pre-defined distance, and wherein the pre-defined distance is selected to determine the amount of electromagnetic coupling.

45. The miniature antenna of claim 38, wherein the first and second planes are perpendicular to a ground plane.

46. The miniature antenna of claim 38, wherein the first and second radiating arms are two of a plurality of radiating arms, and wherein the plurality of radiating arms define a three-dimensional structure.

47. The miniature antenna of claim 46, wherein the plurality of radiating arms each define a grid dimension curve.

48. The miniature antenna of claim 47, wherein the antenna comprises four radiating arms that form the sides of a rhombic structure.

49. The miniature antenna of claim 48, wherein the rhombic structure defines an open top portion and an open bottom portion.

50. The miniature antenna of claim 48, further comprising a common feeding portion coupled to the radiating arms and including a feeding point to coupled the antenna to a transmission medium.

51. The miniature antenna of claim 50, wherein the common feeding portion comprises a rectangular portion coupled to the radiating arms and an intersecting portion extending inwardly from the rectangular portion, wherein the intersecting portion comprises the feeding point.

52. The miniature antenna of claim 48, further comprising a common top-loading portion coupled to the radiating arms.

53. The miniature antenna of claim 38, wherein the first plane is parallel to the second plane.

54. The miniature antenna of claim 53, wherein the first radiating arm is coupled to the second radiating arm.

55. The miniature antenna of claim 54, further comprising a common feeding portion coupled to the first and second radiating arms and including a feeding point to couple the antenna to a transmission medium.

56. The miniature antenna of claim 55, wherein the common feeding portion comprises a rectangular portion coupled to the radiating arms and an intersecting portion extending inwardly from the rectangular portion, wherein the intersecting portion comprises the feeding point.

57. The miniature antenna of claim 53, wherein the first and second radiating arms are two of a plurality of radiating arms that each define a grid dimension curve, wherein the plurality of radiating arms are aligned in parallel planes.

58. The miniature antenna of claim 57, wherein the grid dimension curve in each radiating arm is coupled to the grid dimension curve in an adjacent radiating arm.

59. The miniature antenna of claim 58, wherein one of the radiating arms comprises in&

1-ud.es a feeding point to coupled the antenna to a transmission medium and at least another of the radiating arms is coupled to a ground potential.

60. The miniature antenna of claim 58, wherein each of the grid dimension curves have a pre-selected conductor length that is selected to result in a 180 degree phase shift in current between adjacent radiating arms.

61. The miniature antenna of claim 58, wherein a middle radiating arm comprises a feeding point to coupled the antenna to a transmission medium.

62. The miniature antenna of claim 61, wherein the middle radiating arm has a first pre-selected conductor length and the rest of the radiating arms have a second pre-selected conductor length, and wherein the first and second conductor lengths are selected to result in a 90 degree phase shift in current between the middle radiating arm and two adjacent radiating arms.

63. The miniature antenna of claim 62, wherein the middle radiating arm further comprises a solid conductor coupled to the grid dimension curve, and wherein the solid conductor comprises the feeding point.

64. The miniature antenna of claim 47, wherein the antenna comprises six radiating arms that form the sides of a polyhedral structure.

65. The miniature antenna of claim 64, wherein the polyhedral structure is a cube.

66. The miniature antenna of claim 64, wherein the grid dimension curves defined by the six radiating arms are coupled together to form a continuous conductor having an end point, and wherein the end point of the continuous conductor is a feeding point for the antenna.

67. The miniature antenna of claim 47, wherein the radiating arms of the antenna define a pyramid.

68. The miniature antenna of claim 47, wherein the radiating arms of the antenna define a rhombic structure.

69. The miniature antenna of claim 38, further comprising:

a third radiating arm that defines a third grid dimension curve within a third plane; and

a fourth radiating arm that defines a fourth grid dimension curve within a fourth plane;

wherein the first radiating arm is an active radiating arm that comprises a feeding point to coupled the antenna to a transmission medium, and

wherein the second, third and fourth radiating arms are parasitic radiating arms coupled to a ground potential.

70. The miniature antenna of claim 69, further comprising:

a first top-loading portion coupled to the first radiating arm;

a second top-loading portion coupled to the second radiating arm;

a third top-loading portion coupled to the third radiating arm; and

a fourth top-loading portion coupled to the fourth radiating arm.

71. The miniature antenna of claim 70, wherein the top-loading portions are electromagnetically coupled.

72. The miniature antenna of claim 38, wherein:

the first grid dimension curve has a grid dimension (D_g1) greater than one;

$D_{g<br><br><br><br>1}=\frac{\log <br><br>\left(N<br><br><br><br>21\right)-\log <br><br>\left(N<br><br><br><br>11\right)}{\log <br><br>\left(L<br><br><br><br>21\right)-\log <br><br>\left(L<br><br><br><br>11\right)};<br><br>$

L11 is a length of square cells of a first grid positioned over the first grid dimension curve such that the first grid completely covers the first grid dimension curve;

N11 is the number of the square cells of the first grid that enclose at least a portion of the first grid dimension curve;

L21 is a length of square cells of a second grid positioned over the first grid dimension curve such that the second grid completely covers the first grid dimension curve;

N21 is the number of the square cells of the second grid that enclose at least a portion of the first grid dimension curve;

the first grid and the second grid are each positioned such that no entire row or column on a perimeter of either of the grids fails to enclose at least a portion of the first grid dimension curve;

the first grid comprises twenty-five cells;

the second grid has four times the number of cells as the first grid;

L21 is equal to 0.5 L11;

the second grid dimension curve has a grid dimension (D_g2) greater than one;

$D_{g<br><br><br><br>2}=\frac{\log <br><br>\left(N<br><br><br><br>22\right)-\log <br><br>\left(N<br><br><br><br>12\right)}{\log <br><br>\left(L<br><br><br><br>22\right)-\log <br><br>\left(L<br><br><br><br>12\right)};<br><br>$

L12 is a length of square cells of a first grid positioned over the second grid dimension curve such that the first grid completely covers the second grid dimension curve;

N12 is the number of the square cells of the first grid that enclose at least a portion of the second grid dimension curve;

L22 is a length of square cells of a second grid positioned over the second grid dimension curve such that the second grid completely covers the second grid dimension curve;

N22 is the number of the square cells of the second grid that enclose at least a portion of the second grid dimension curve;

the first grid and the second grid are each positioned such that no entire row or column on a perimeter of either of the grids fails to enclose at least a portion of the second grid dimension curve;

the first grid comprises twenty-five cells;

the second grid has four times the number of cells as the first grid; and

L22 is equal to 0.5 L12.

73. The miniature antenna of claim 72, wherein the first and second grid dimension curves each have a grid dimension greater than 1.2.

74. The miniature antenna of claim 72, wherein the first and second grid dimension curves each have a grid dimension greater than 1.5.

75. The miniature antenna of claim 72, wherein the first and second grid dimension curves each have a grid dimension greater than 1.65.

76. The miniature antenna of claim 72, wherein the first and second grid dimension curves each have a grid dimension greater than 1.9.

77. A miniature antenna, comprising:

a radiating arm that defines at least one grid dimension curve;

the radiating arm forming a non-planar structure;

the radiating arm including a feeding point to coupled the antenna to a transmission medium;

wherein the physical dimensions of the antenna are smaller than one-fifteenth of a free-space operating wavelength of the antenna;

and

wherein the grid dimension curve defines a space-filling curve;

wherein the space-filling curve comprises at least ten segments;

wherein each of the at least ten segments forms an angle with an adjacent segment of the at least ten segments and is shorter than one-tenth the free-space operating wavelength.

78. The miniature antenna of claim 77, wherein:

at least one of the at least one grid dimension curve has a grid dimension (D_g) greater than one;

$D_g=\frac{\log <br><br>\left(N<br><br><br><br>2\right)-\log <br><br>\left(N<br><br><br><br>1\right)}{\log <br><br>\left(L<br><br><br><br>2\right)-\log <br><br>\left(L<br><br><br><br>1\right)};<br><br>$

L1 is a length of square cells of a first grid positioned over the at least one grid dimension curve such that the first grid completely covers the at least one of the at least one grid dimension curve;

N1 is the number of the square cells of the first grid that enclose at least a portion of the at least one of the at least one grid dimension curve;

L2 is a length of square cells of a second grid positioned over the at least one of the at least one grid dimension curve such that the second grid completely covers the at least one of the at least one grid dimension curve;

N2 is the number of the square cells of the second grid that enclose at least a portion of the at least one of the at least one grid dimension curve;

the first grid and the second grid are each positioned such that no entire row or column on a perimeter of either of the grids fails to enclose at least a portion of the at least one of the at least one grid dimension curve;

the first grid comprises twenty-five cells;

the second grid has four times the number of cells as the first grid; and

L2 is equal to 0.5 L1.

79. The miniature antenna of claim 78, wherein the grid dimension curve has a grid dimension greater than 1.2.

80. The miniature antenna of claim 78, wherein the grid dimension curve has a grid dimension greater than 1.5.

81. The miniature antenna of claim 78, wherein the grid dimension curve has a grid dimension greater than 1.65.

82. The miniature antenna of claim 78, wherein the grid dimension curve has a grid dimension greater than 1.9.

83. The miniature antenna of claim 77, wherein the radiating arm forms a cylindrical structure.

84. The miniature antenna of claim 83, wherein the radiating arm is a solid conductor shaped to form the cylindrical structure, and wherein the solid conductor defines a slot and the slot defines the grid dimension curve.

85. The miniature antenna of claim 77, wherein the radiating arm forms a folded structure.

86. The miniature antenna of claim 77, wherein the radiating arm comprises:

a first vertical portion that defines a first grid dimension curve;

a second vertical portion that defines a second grid dimension curve; and

a top portion that couples the first vertical portion to the second vertical portion;

wherein the first vertical portion comprises the feeding point and the second vertical portion is coupled to a ground potential.

87. The miniature antenna of claim 86, wherein the top portion is a solid conductor.

88. The miniature antenna of claim 86, wherein the top portion defines a third grid dimension curve.

89. The miniature antenna of claim 86, wherein the radiating arm further comprises:

at least one additional vertical portion that defines a grid dimension curve and that is coupled between the top portion and the ground potential.