Wireless power range increase using parasitic antennas

• US 8,766,483 B2
• Filed: 11/26/2008
• Issued: 07/01/2014
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Cook, Nigel P., Sieber, Lukas, Widmer, Hanspeter
• Primary Examiner(s): AMAYA, CARLOS DAVID
• Application Number:
  US12/323,479
• Publication Number:
  US 20090134712A1
• Time in Patent Office: 2,043 Days
• Field of Search: 307/104, 320/108
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices

Abstract

Wireless power transfer is created using a first antenna that is part of a magnetic resonator, to create a magnetic field in an area of the first antenna. One or more parasitic antennas repeats that power to create local areas where the power is more efficiently received.

Claims

1. A system for wirelessly transferring power to a device, the system comprising:

a wireless power transmitter including a transmitting antenna of a first dimension, the transmitting antenna being configured to resonate at a resonant frequency and to transmit wireless power via a first wireless field; and

a repeater antenna having a second dimension that is different than the first dimension, the repeater antenna being configured to resonate at substantially the same resonant frequency and retransmit wireless power received from the wireless power transmitter via a second wireless field, the repeater antenna having a short-circuited portion configured to adjust a resonant frequency of the repeater antenna.

2. The system as in claim 1, wherein said repeater antenna includes an inductive loop and a capacitor having a capacitance value.

3. The system as in claim 2, wherein said inductive loop comprises a stranded wire with strands that are electrically isolated from one another.

4. The system as in claim 2, wherein said inductive loop comprises a material that increases an effective cross sectional area of a wire used for the antenna without increasing an actual cross sectional area of the wire.

5. The system as in claim 2, wherein said repeater antenna includes a tuning part that is adjustable to change a resonant frequency of said repeater antenna.

6. The system as in claim 5, wherein said tuning part includes a component having a variable capacitance.

7. The system as in claim 6, wherein said component having the variable capacitance includes a switched capacitor.

8. The system as in claim 5, wherein said tuning part is configured to only decrease the resonant frequency.

9. The system as in claim 5, wherein said shorted-circuit portion short circuits a portion of said inductive loop.

10. The system as in claim 9, wherein said tuning part has a variable size and is configured to change an area of the inductive loop.

11. The system as in claim 10, wherein said tuning part is triangular.

12. The system as in claim 1, wherein said transmitting antenna surrounds a perimeter of a room.

13. The system as in claim 12, wherein said transmitting antenna is at different height levels in the room.

14. The system as in claim 1, wherein said wireless power transmitter includes a frequency generator and a matching system, said matching system including a coupling transformer and a capacitor on a secondary side of said wireless power transmitter.

15. The system as in claim 1, wherein said second size is smaller than said first size.

16. The system as in claim 1, wherein said repeater antenna includes an inductive loop having a capacitance value.

17. The system as in claim 1, wherein the transmitting antenna encompasses a first antenna area, and wherein the repeater antenna is configured to retransmit the received power in a second antenna area that corresponds to an area within the first antenna area.

18. The system as in claim 1, wherein at least one of the transmitting antenna or the repeater antenna comprises at least one tapped coil that is adjustable to vary a level of coupling between the transmitting antenna and the repeater antenna.

19. The system as in claim 1, wherein the repeater antenna is configured to have a same orientation with respect to at least one of the first wireless field or the second wireless field.

20. The system as in claim 1, wherein the transmitting antenna and the repeater antenna are substantially coplanar.

21. A system for wirelessly transferring power from a transmitting antenna to a device, the system comprising:

a repeater antenna having a first dimension, the repeater antenna being tuned to resonate at a resonant frequency and receive wireless power transferred via a first wireless field from the transmitting antenna having a second dimension that is different than the first dimension, the transmitting antenna being configured to resonate at substantially the same resonant frequency, the repeater antenna configured to retransmit the received wireless power via a second wireless field, the repeater antenna having a short-circuited portion configured to adjust the resonant frequency of the repeater antenna.

22. The system as in claim 21, wherein said repeater antenna includes an inductive loop and a capacitor having a capacitance.

23. The system as in claim 22, wherein said inductive loop comprises a material that increases an effective cross sectional area of a wire used for the repeater antenna without increasing an actual cross sectional area of the wire.

24. The system as in claim 23, wherein said inductive loop comprises a stranded wire with strands that are electrically isolated from one another.

25. The system as in claim 22, wherein said repeater antenna includes a tuning part that is adjustable to change a resonant frequency of said repeater antenna.

26. The system as in claim 25, wherein said tuning part includes a component having a variable capacitance.

27. The system as in claim 25, wherein said tuning part is configured to only decrease said resonant frequency.

28. The system as in claim 27, wherein said component having the variable capacitance includes a switched capacitor.

29. The system as in claim 25, wherein said short-circuited portion short circuits a portion of said inductive loop.

30. The system as in claim 29, wherein said tuning part has a variable size and is configured to change an area of the inductive loop.

31. The system as in claim 30, wherein said tuning part is triangular in its outer shape.

32. The system as in claim 21, wherein said repeater antenna includes an inductive loop having a capacitance value.

33. The system as in claim 21, wherein the transmitting antenna encompasses a first antenna area, and wherein the repeater antenna is configured to retransmit the received power in a second antenna area that corresponds to an area within the first antenna area.

34. The system as in claim 21, wherein at least one of the transmitting antenna or the repeater antenna comprises at least one tapped coil that is adjustable to vary a level of coupling between the transmitting antenna and the repeater antenna.

35. The system as in claim 21, wherein the repeater antenna is configured to have a same orientation with respect to at least one of the first wireless field or the second wireless field.

36. The system as in claim 21, wherein the transmitting antenna and the repeater antenna are substantially coplanar.

40. The system as in claim 21, wherein the capacitance of the wireless power transmitter corresponds to the capacitance of the antenna loop.

37. A system, comprising:

a wireless power transmitter configured to generate a wireless power transmission field at a specified frequency; and

a transmitting antenna coupled to the wireless power transmitter and having a first antenna area, the transmitting antenna being configured to transmit wireless power at the specified frequency, the transmitting antenna having an antenna loop that extends around a perimeter of the first antenna area, the antenna loop having an inductance, the transmitting antenna having a capacitance, the inductance and the capacitance corresponding to an LC value causing the transmitting antenna to be substantially resonant at the specified frequency, the antenna loop having a first section at a first level and a second section at a second level that is different than the first level.

38. A system as in claim 37, further comprising a parasitic antenna, the parasitic antenna having a second antenna area that is smaller than the first antenna area, the parasitic antenna configured to retransmit the wireless power in the second antenna area.

39. The system as in claim 37, wherein the antenna loop includes a third section which extends between the first and second sections.

41. The system as in claim 37, further comprising a parasitic antenna having a portion that is short-circuited to adjust a resonant frequency of the parasitic antenna.

42. The system as in claim 37, further comprising a parasitic antenna, wherein at least one of the transmitting antenna or the parasitic antenna comprises at least one tapped coil that is adjustable to vary a level of coupling between the transmitting antenna and the parasitic antenna.

43. The system as in claim 37, further comprising a parasitic antenna, the parasitic antenna configured to have a same orientation with respect to the wireless power transmission field.

44. A method of wireless transferring power, comprising:

transmitting wireless power from a first antenna via a first wireless field, the first antenna having a first dimension and configured to resonate at a resonant frequency;

retransmitting power received via the first wireless field with a second antenna within a range of the first antenna to a portable device to power the portable device via a second wireless field, the second antenna having a second dimension that is different than the first dimension and being configured to resonate at the resonant frequency; and

short circuiting a portion of the second antenna to adjust the resonant frequency of the second antenna.

45. The method as in claim 44, wherein said first antenna has a larger outer size than said second antenna.

46. The method as in claim 44, further comprising using a material that increases an effective cross sectional area of a wire used for the second antenna without increasing an actual cross sectional area of the wire.

47. The method as in claim 44, wherein the first transmitting antenna surrounds a perimeter of a room.

48. The method as in claim 47, wherein said first transmitting antenna is at different height levels in the room.

49. The method as in claim 44, further comprising tuning a resonant frequency of a repeater antenna.

50. The method as in claim 49, wherein said tuning comprises changing a value of a component having a variable capacitance.

51. The method as in claim 49, wherein said tuning comprises short circuiting a portion of said inductive loop.

52. The method as in claim 44, further comprising adjusting a level of coupling between the first antenna and the second antenna.

53. The method as in claim 44, further comprising adjusting at least one of the first antenna or the second antenna such that the first antenna and the second antenna are coplanar.

54. A system for wirelessly transferring power to a device, the system comprising:

means for transmitting wireless power via a first wireless field, the means for transmitting wireless power having a first dimension and configured to resonate at a resonant frequency;

means for retransmitting wireless power received from the means for transmitting wireless power in an area via a second wireless field, the means for retransmitting wireless power having a second dimension that is different than the first dimension and being configured to resonate at substantially the same resonant frequency; and

means for short circuiting the means for retransmitting to adjust a resonant frequency of the means for retransmitting.

55. A system for wirelessly transferring power from a transmitting antenna to a device, the system comprising:

means for retransmitting wireless power via a first wireless field in an area, the means for retransmitting wireless power having a first dimension and being configured to receive power via a second wireless field from the transmitting antenna configured to resonate at a resonant frequency, the transmitting antenna having a second dimension that is different than the first dimension;

means for short circuiting the means for retransmitting to adjust a resonant frequency of the means for retransmitting; and

means for tuning the means for retransmitting wireless power to receive the wireless power from the second wireless field and cause the means for retransmitting wireless power to resonate at substantially the same resonant frequency.

56. A method of wirelessly transferring power to a device, the method comprising:

retransmitting wireless power received via a first wireless field with a repeater antenna within an area of the repeater antenna, the repeater antenna having a first dimension and being configured to receive power via a second wireless field from a transmitting antenna configured to resonate at a resonant frequency, the transmitting antenna having a second dimension that is different than the first dimension;

adjusting a resonant frequency of the repeater antenna through a short circuited portion of the repeater antenna; and

tuning the repeater antenna to resonate at substantially the same resonant frequency and receive the wireless power via the second wireless field.