SPACE-FILLING MINIATURE ANTENNAS

• US 20110181478A1
• Filed: 03/02/2011
• Published: 07/28/2011
• Est. Priority Date: 01/19/2000
• Status: Active Grant

• Current Assignee: Fractus SA
• Original Assignee: Fractus SA
• Inventors: ROZAN, EDOUARD JEAN LOUIS, PROS, Jaime ANGUERA, BALIARDA, CARLES PUENTE
• Granted Patent: US 8,610,627 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• 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 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 5/25 Ultra-wideband [UWB] systems, e.g. multiple resonance systems; Pulse systems
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• 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 novel geometry, the geometry of Space-Filling Curves (SFC) is defined in the present invention and it is used to shape a part of an antenna. By means of this novel technique, the size of the antenna can be reduced with respect to prior art, or alternatively, given a fixed size the antenna can operate at a lower frequency with respect to a conventional antenna of the same size.

Claims

1. An apparatus comprising:

a portable communication device;

an antenna, the antenna being included entirely within the portable communication device;

wherein an edge of the antenna is shaped as a substantially non-periodic curve;

wherein said substantially non-periodic curve comprises a multiplicity of connected segments, each segment is shorter than one tenth of at least one operating free-space wavelength of the antenna;

wherein the antenna radiates at multiple different operating wavelengths;

wherein at least one of the operating wavelengths corresponds to an operating wavelength of a cellular telephone system; and

wherein the antenna is configured to radiate across at least two cellular telephone system frequency bands.

2. The apparatus as set forth in claim 1, wherein said portable communication device is a cell phone.

3. The apparatus as set forth in claim 2, wherein the antenna includes a matching network between an element and an input connector or transmission line.

4. The apparatus as set forth in claim 3, wherein said multiplicity of connected segments comprise an irregular arrangement of at least ten segments, and further wherein no two adjacent and connected segments of said multiplicity of connected segments form another longer straight segment.

5. The apparatus as set forth in claim 4, wherein each pair of adjacent segments forms a bend such that said substantially non-periodic curve has a physical length larger than that of any straight line that can be fitted in the same area in which the multiplicity of connected segments are arranged, and so that the substantially non-periodic curve can be fitted inside a radian sphere of said at least one operating free-space wavelength of the antenna.

6. The apparatus as set forth in claim 5, wherein a first frequency band of said at least two cellular telephone system frequency bands is a frequency band at approximately 1900 MHz.

7. The apparatus as set forth in claim 6, wherein a second frequency band of said at least two cellular telephone system frequency bands is a frequency band at approximately 1800 MHz.

8. The apparatus as set forth in claim 7, wherein the antenna is a patch antenna comprising:

a ground plane;

a conducting patch substantially parallel to the ground plane; and

wherein a perimeter of the conducting patch is defined by the substantially non-periodic curve.

9. The apparatus as set forth in claim 8, wherein the substantially non-periodic curve features a box-counting dimension greater than 1.3.

10. The apparatus as set forth in claim 8, wherein a distance between the conducting patch and the ground plane is below one quarter of said at least one operating free-space wavelength.

11. The apparatus as set forth in claim 5, wherein the antenna is adapted to radiate across a GSM 900 system frequency band, a GSM 1800 system frequency band and a UMTS system frequency band.

12. The apparatus as set forth in claim 11, wherein the antenna is a monopole antenna comprising a radiating arm and a ground counterpoise in which an edge of said radiating arm is shaped as the substantially non-periodic curve.

13. The apparatus as set forth in claim 12, wherein the substantially non-periodic curve features a box-counting dimension greater than 1.4.

14. The apparatus as set forth in claim 13, wherein said substantially non-periodic curve is shaped so that the arrangement of said multiplicity of connected segments is not self-similar with respect to the entire substantially non-periodic curve.

15. The apparatus as set forth in claim 14, wherein the substantially non-periodic curve extends across a surface lying on more than one plane.

16. The apparatus as set forth in claim 15, wherein the substantially non-periodic curve is printed over a dielectric substrate.

17. The apparatus as set forth in claim 2, wherein the antenna is adapted to radiate across at least three cellular telephone system frequency bands within the 800 MHz-3600 MHz frequency range.

18. The apparatus as set forth in claim 17, wherein a first frequency band of said at least two cellular telephone system frequency bands is at approximately 1900 MHz and a second frequency band of said at least two cellular telephone system frequency bands is at approximately 2100 MHz.

19. The apparatus as set forth in claim 18, wherein at least radiating element of said antenna comprises a printed conductive sheet on a printed circuit board.

56. The apparatus as set forth in claim 3, wherein said substantially non-periodic curve shapes less than an entire edge of the antenna.

57. The apparatus as set forth in claim 3, wherein said substantially non-periodic curve shapes an entire edge of the antenna.

20. An apparatus comprising:

a portable communication device;

an antenna, the antenna being entirely included in the portable communication device;

wherein the antenna comprises a radiating element a perimeter of which is defined by a multi-segment, irregular curve including a plurality of segments, each of said segments being spatially arranged such that no two adjacent and connected segments form another longer straight segment and none of said segments intersects with another segment other than at the beginning and at the end of said multi-segment, irregular curve to form a closed loop;

wherein the antenna radiates at multiple different operating wavelengths;

wherein each segment of said plurality of segments is shorter than one tenth of a longest operating free-space wavelength of said multiple different operating wavelengths;

wherein the multi-segment curve has a box counting dimension larger than one;

wherein a first of the multiple different operating wavelengths corresponds to an operating wavelength of a first cellular telephone system; and

wherein a second of the multiple different operating wavelengths corresponds to an operating wavelength of a second cellular telephone system.

21. The apparatus as set forth in claim 20, wherein the antenna is adapted to radiate across at least three cellular telephone system frequency bands.

22. The apparatus as set forth in claim 21, wherein said portable communication device is a cell phone.

23. The apparatus as set forth in claim 22, wherein the antenna includes a matching network between the radiating element and an input connector or transmission line.

24. The apparatus as said forth in claim 22, wherein said multi-segment, irregular curve features a box-counting dimension larger than 1.4.

25. The apparatus as said forth in claim 22, wherein the multi-segment, irregular curve includes at least 25 segments.

26. The apparatus as set forth in claim 22, wherein the radiating element is a radiating arm of a monopole antenna.

27. The apparatus as set forth in claim 22, wherein the radiating element is a conducting patch of a patch antenna.

28. The apparatus as set forth in claim 22, wherein said multi-segment, irregular curve is shaped so that the arrangement of said plurality of segments is not self-similar with respect to the entire multi-segment, irregular curve.

29. The apparatus as set forth in claim 20, wherein each pair of adjacent segments forms a bend such that said multi-segment, irregular curve has a physical length larger than that of any straight line that can be fitted in the same area in which the plurality of segments are arranged, and so that the resulting multi-segment, irregular curve can be fitted inside a radian sphere of said longest operating free-space wavelength of the antenna.

30. The apparatus as set forth in claim 29, wherein said portable communication device is a cell phone.

31. The apparatus as set forth in claim 30, wherein the antenna is adapted to radiate across at least three cellular telephone system frequency bands.

32. The apparatus as set forth in claim 30, wherein the antenna is adapted to radiate and receive electromagnetic waves across at least four cellular telephone system frequency bands.

33. The apparatus as said forth in claim 30, wherein said multi-segment, irregular curve features a box-counting dimension larger than 1.3.

34. The apparatus as said forth in claim 30, wherein the multi-segment, irregular curve includes at least 20 segments.

35. The apparatus as set forth in claim 30, wherein the multiple different operating wavelengths include GSM 850 and GSM 900.

36. The apparatus as set forth in claim 29, wherein the antenna includes a matching network between the radiating element and an input connector or transmission line.

37. The apparatus as said forth in claim 36, wherein said multi-segment, irregular curve features a box-counting dimension larger than 1.2, and further wherein the box-counting dimension is computed as the slope of a substantially straight portion of a line in a log-log graph over at least an octave of scales on the horizontal axes of the log-log graph.

38. The apparatus as set forth in claim 36, wherein the antenna is adapted to radiate across at least three cellular telephone system frequency bands.

39. The apparatus as set forth in claim 36, wherein the antenna is adapted to radiate and receive electromagnetic waves across at least four cellular telephone system frequency bands.

40. The apparatus as set forth in claim 36, wherein the antenna is adapted to radiate electromagnetic waves across at least five cellular telephone system frequency bands.

54. The apparatus as set forth in claim 26, wherein said multi-segment, irregular curve shapes a perimeter of said radiating arm.

55. The apparatus as set forth in claim 27, wherein said multi-segment, irregular curve shapes a perimeter of an arm of said conducting patch.

41. An apparatus comprising:

a portable communication device;

an antenna, the antenna being included entirely within the portable communication device;

wherein an edge of the antenna is shaped as a substantially non-periodic curve;

wherein said substantially non-periodic curve comprises a multiplicity of connected segments, each segment is shorter than one tenth of at least one operating free-space wavelength of the antenna;

wherein the antenna radiates at multiple different operating wavelengths;

wherein at least one of the operating wavelengths corresponds to an operating wavelength of a cellular telephone system;

wherein the antenna is configured to radiate across at least three cellular telephone system frequency bands; and

wherein the portable communications device comprises a cellular telephone.

42. The apparatus of claim 41, wherein the antenna operates in a frequency band at approximately 850 MHz.

43. The apparatus of claim 41, wherein the antenna resonates at least at two different operating wavelengths, wherein a first of said operating wavelengths corresponds to an operating wavelength of a first cellular telephone system and a second of said operating wavelengths corresponds to an operating wavelength of a second cellular telephone system.

44. The apparatus of claim 41, wherein the antenna operates in a frequency band at approximately 1900 MHz.

45. The apparatus of claim 44, wherein the substantially non-periodic curve is arranged over two or more surfaces.

46. The apparatus of claim 44, wherein said substantially non-periodic curve features a box-counting dimension larger than 1.3, the box-counting dimension is computed as the slope of a substantially straight portion of a line in a log-log graph over at least an octave of scales on the horizontal axes of the log-log graph.

47. The apparatus of claim 41, wherein the antenna operates in at least four cellular telephone system frequency bands.

48. The apparatus of claim 47, wherein said substantially non-periodic curve features a box-counting dimension larger than 1.2, the box-counting dimension is computed as the slope of a substantially straight portion of a line in a log-log graph over at least an octave of scales on the horizontal axes of the log-log graph.

49. The apparatus of claim 41, wherein the antenna is adapted to radiate electromagnetic waves across at least five cellular telephone system frequency bands.

50. The apparatus of claim 49, wherein the antenna comprises multiple elements.

51. The apparatus of claim 50, wherein the multiple elements include a ground plane.

52. The apparatus of claim 43, wherein said substantially non-periodic curve shapes less than an entire perimeter of a radiating arm of the antenna.

53. The apparatus of claim 43, wherein said substantially non-periodic curve shapes an entire perimeter of a radiating arm of the antenna.