Transmitters and receivers for wireless energy transfer

• US 20090079268A1
• Filed: 09/16/2008
• Published: 03/26/2009
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Nigel Power LLC (Qualcomm, Inc.)
• Original Assignee: Nigel Power LLC (Qualcomm, Inc.)
• Inventors: Widmer, Hanspeter, Sieber, Lukas, Cook, Nigel P., Dominiak, Stephen
• Granted Patent: US 8,378,523 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

Techniques for wireless power transmission. An antenna has a part that amplifies a flux to make the antenna have a larger effective size than its actual size.

Claims

1. An system for receiving magnetic transmission of power, comprising:

a wire loop antenna, having a wire formed into at least one loop forming an inductance, and having a capacitance, said wire loop antenna having an LC value tuned for receiving a magnetic field of a first specified frequency, and producing an output based on receiving said magnetic field that includes electrical power; and

said antenna including a first electrical part associated with said wire loop antenna which increases an equivalent radius of the wire loop portion of said antenna without increasing an actual radius of a wire loop antenna.

2. A system as in claim 1, wherein said wire loop is a rectangular loop.

3. A system as in claim 2, wherein said rectangular loop has rounded edges.

4. An antenna system as in claim 1, wherein said first electrical part causes a magnetic field to be created as though said wire loop had an equivalent radius, greater than its physical radius.

5. An antenna system as in claim 1, wherein said first electrical part includes a part formed of a ferrite material.

6. An antenna system as in claim 1, wherein said first electrical part includes a part formed of a material that adds additional magnetic flux to an already existing flux.

7. An antenna system as in claim 1, wherein said first electrical part is a flux magnification part.

8. An antenna system as in claim 7, wherein said flux magnification part has a relative permeability, and the flux magnification is increased by the square root of the relative permeability.

9. An antenna system as in claim 7, wherein said flux magnification part includes a rod, and an amount of flux magnification is related to a length of said rod.

10. A system as in claim 1, further comprising a housing, adapted for housing mobile electronics, and wherein said wire loop antenna is oriented to surround at least one area of said housing.

11. A system as in claim 1, further comprising a connection to a wireless power circuit, carrying said output.

12. The system as in claim 10, wherein said wire loop antenna surrounds a complete outer perimeter of said housing.

13. A system as in claim 10, wherein said housing is formed of a metallic material, and said antenna is separated from said metallic material.

14. A system as in claim 13, wherein said separation forms a gap, of a size through which magnetic fields can escape.

15. A system as in claim 13, wherein said loop antenna is separable from said housing and movable relative thereto.

16. A system as in claim 13, further comprising a ferrite portion, coupled to said housing, and holding at least a part of said antenna separated from said housing.

17. A system as in claim 9, further comprising a housing, adapted for housing mobile electronics, and said rod is within said housing, wherein said wire loop antenna is wound around said rod.

18. A system as in claim 1, further comprising at least one opening in said housing, allowing magnetic fields to pass through said opening and to interact with said rod.

19. A system as in claim 18, wherein said Rod is formed of a ferrite material.

20. A system as in claim 17, further comprising a slot in said housing.

21. A system as in claim 20, wherein said housing is formed of a conductive material.

22. A method for receiving a magnetic transmission of power, comprising:

using a resonator with an LC ratio formed by a wire loop antenna tuned to a value that is resonant with a frequency of a magnetic field, said resonator having a wire loop forming an inductance, and having a capacitance;

said using comprising increasing an equivalent radius of the wire loop portion of said antenna without increasing an actual radius of a wire loop antenna;

receiving said magnetic field and producing usable power based thereon;

applying said power to a load, to power said load based on receiving said magnetic field that includes electrical power.

23. A method as in claim 22, wherein said wire loop is a rectangular loop.

24. A method as in claim 23, wherein said rectangular loop has rounded edges.

25. A method as in claim 23, wherein said increasing comprises adding additional magnetic flux to an already existing flux.

26. A method as in claim 23, further comprising magnifying a flux created by said resonator.

27. A method as in claim 23, further comprising a housing, adapted for housing mobile electronics, and further comprising using said wire loop antenna which is oriented to surround at least one area of said housing.

28. The method as in claim 27, wherein said wire loop antenna surrounds a complete outer perimeter of said housing.

29. A method as in claim 27, wherein said housing is formed of a metallic material, and further comprising using said wire loop antenna which is separated from said metallic material.

30. A method as in claim 29, further comprising using a gap between said wire loop antenna and said metallic material, to receive magnetic fields can escape.

31. A method as in claim 22, wherein said loop antenna is separable from said housing and further comprising allowing moving said loop antenna movable relative to said housing.

32. An antenna system for magnetic power transfer, comprising:

a resonator formed of an inductive loop and a capacitor element; and

a first compensating structure, which compensates for effects of extraneous objects on the resonator.

33. A system as in claim 32, wherein said antenna has a Q factor of greater than 1500.

34. In the antenna as in claim 32, wherein said antenna system has a Q factor of greater than 2000.

35. A system as in claim 34, wherein said antenna is a single loop antenna.

36. A system as in claim 32, wherein said inductive loop has a rectangular shape.

37. A method, comprising:

determining if an environment will have dielectric losses or Eddy current losses;

selecting a resonator with high inductance to capacitance ratio resonator for an environment where eddy current losses are predominant, based on said determining;

selecting a low inductance to capacitance ratio resonator for an environment where dielectric losses are predominant, based on said determining; and

using said selected resonator as part of a system to retrieve electrical power from a magnetic power transmission.

38. A method as in claim 37, wherein said low inductance to capacitance ratio antenna has more than 2 turns of an inductive loop.

39. A method as in claim 37, wherein said high inductance to capacitance ratio antenna has two or fewer turns of an inductive loop.

40. A method as in claim 37, wherein said antenna has a Q greater than 1500.

41. A system for receiving wireless power, comprising:

a housing, adapted for housing mobile electronics;

a loop antenna portion, oriented to surround at least one area of said housing; and

a connection to a wireless power circuit.

42. The system as in claim 41, wherein at least one portion of said antenna surrounds a complete outer perimeter of said housing.

43. A system as in claim 42, wherein said housing is formed of a nonmetallic material, and said antenna is physically in contact with said nonmetallic material.

44. A system as in claim 41, wherein said housing is formed of a metallic material, and said antenna is separated from said metallic material.

45. A system as in claim 44, wherein said separation forms a gap, of a size through which magnetic currents can escape.

46. A system as in claim 41, wherein said loop antenna is separable from said housing and movable relative therewith.

47. A system as in claim 41, further comprising a ferrite portion, coupled to said housing, and holding at least a part of said antenna.

48. A system for receiving wireless power, comprising:

a housing, adapted for housing mobile electronics;

a coil winding form, extending across said housing from at least a first side of said housing to a second side of said housing;

a coil, wound around said form; and

at least one opening and said housing, allowing magnetic fields to interact with said form.

49. A system as in claim 48, wherein said form is formed of a ferrite material.

50. A system as in claim 48, further comprising a slot in said housing.

51. A system as in claim 48, wherein said housing is formed of a conductive material.

52. A system as in claim 48, wherein said form is a cylindrical shaped form.

53. A system, comprising:

a first layer of a first material which converts mechanical strain to electrical energy;

a second layer, in mechanical contact with said first layer, and formed of a second material which is sensitive to, and caused to change in position by, an applied magnetic field;

an output terminal, connected to receive said electrical energy from said first layer.

54. The system as in claim 53, wherein said second layer is an electrically conductive magnetostrictive material.

55. The system as in claim 53, wherein said first layer is a piezoelectric material.

56. A system as in claim 53, wherein said output terminal is connected directly to said second layer.

57. A system as in claim 56, wherein there is a third layer formed of said first material, and said second layer is sandwiched between said first layer and said third layer, said first material is electrically conductive, and said output terminals are connected between said first and third layers of said first material.

58. A system as in claim 57, wherein said first material is arranged such that a varying magnetic field compresses said second part.