Systems and methods for wirelessly projecting power using multiple in-phase current loops

• US 6,570,541 B2
• Filed: 12/07/2000
• Issued: 05/27/2003
• Est. Priority Date: 05/18/1998
• Status: Expired due to Fees

• Current Assignee: DB Tag Incorporated
• Original Assignee: DB Tag Incorporated
• Inventors: Dettloff, Wayne D.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US09/732,397
• Publication Number:
  US 20010000960A1
• Time in Patent Office: 901 Days
• Field of Search: H01/Q 1.112, 343/742, 343/741, 343/866, 343/867, 343/895
• US Class Current: 343/742
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• 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
• CPC Class Codes: H01Q 7/04 Screened antennas H01Q7/02, H01Q7/06 take precedence

Abstract

First and second spaced apart in-phase current loops at least partially overlap in the axial direction. The first and second current loops may be first and second arrays of in-phase current loops that are spaced apart and at least partially overlap in the axial direction. First and second arrays of arrays also may be provided that are spaced apart from one another and that at least partially overlap in the axial direction. Desirably high mid-field strength may be provided without violating guidelines for far field radiation in the axial direction or in the plane of the loops. A third array of in-phase current loops, an array of third in-phase current loops and/or an array of arrays of third in-phase current loops also may be provided that spaced apart from and at least partially overlapping the second loops in the axial direction, opposite the first loops. Third and fourth arrays of in-phase current loops also may be provided that are spaced apart from one another, at least partially overlap one another in the axial direction, and have different orientation than the first and second current loops, to reduce and preferably minimize nulls in the near field and mid field. A receive antenna also may be provided between the overlapping portions of the first and second current loops. By providing a receive antenna at this position, the effects of the fields that are produced by the current loops on the receive antenna may be reduced and preferably minimized.

Claims

1. A system for wirelessly projecting power to wirelessly power microelectronic devices, the system comprising:

a first array of in-phase current loops that are disposed adjacent to one another to define a first surface and to define a first virtual current loop at a periphery of the first surface that produces a same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, the first surface including a center, wherein two points on the periphery of the first surface and the center define a plane and an axial direction that is normal to the plane; and

a second array of in-phase current loops that are disposed adjacent to one another to define a second surface and to define a second virtual current loop at a periphery of the second surface that produces a same second direction virtual current that is opposite the same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, wherein the first surface is spaced apart from and at least partially overlaps the second surface in the axial direction.

2. The system according to claim 1 wherein at least one of the first and second arrays of in-phase current loops comprises an array of at least two wedge-shaped current loops, each having an outer portion and a pair of sides, the at least two wedge-shaped current loops being disposed adjacent to one another to define a surface such that currents in the outer portions are in-phase and current in adjacent sides of adjacent current loops are out-of-phase.

3. The system according to claim 1 wherein at least one of the first and second arrays of in-phase current loops comprises an array of at least two polygonal current loops, each having a plurality of sides, the at least two polygonal current loops being disposed adjacent to one another to define a surface, such that currents in the sides of the at least two polygonal loops that are adjacent the periphery of the surface are in-phase and current in adjacent sides of adjacent current loops are out-of-phase.

4. The system according to claim 1 wherein at least one of the first and second arrays of in-phase current loops comprises an array of spiral current loops.

5. The system according to claim 1 wherein each of the in-phase current loops is less than a quarter wavelength long.

6. The system according to claim 1 wherein at least one of the first and second arrays of in-phase current loops comprises an array of concentric current loops.

7. The system according to claim 1 wherein least one of the first and second arrays of in-phase current loops comprises an array of stacked current loops.

8. The system according to claim 1 further comprising a driver that drives the first and second arrays of current loops at 13.56 MHz to thereby wirelessly project power.

9. The system according to claim 1 wherein the first and second arrays of in-phase current loops are arranged to provide at least some reinforcement of an electromagnetic near field that is produced by the current loops while producing at least some cancellation of a far field electromagnetic wave that is produced by the current loops.

10. The system according to claim 1 wherein the first and second arrays of in-phase current loops are of same size.

11. The system according to claim 1 wherein the first surface is spaced apart from and completely overlaps the second surface in the axial direction.

12. The system according to claim 10 wherein the first surface is spaced apart from and completely overlaps the second surface in the axial direction.

13. The system according to claim 1 further comprising a receive antenna between overlapping portions of the first and second surfaces.

14. The system according to claim 13 wherein the receive antenna is midway between the overlapping portions of the first and second surfaces.

15. The system according to claim 14 wherein the receive antenna extends parallel to the overlapping portion of the first surface.

16. The system according to claim 1 further comprising:

a third array of in-phase current loops that are disposed adjacent to one another to define a third surface and to define a third virtual current loop at a periphery of the third surface that produces a same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, wherein the third surface is spaced apart from the second surface, is opposite the first surface and at least partially overlaps the second surface in the axial direction.

17. The system according to claim 1 wherein the plane is a first plane and wherein the axial direction is a first axial direction, the system further comprising:

a third array of in-phase current loops that are disposed adjacent to one another to define a third surface and to define a third virtual current loop at a periphery of the third surface that produces a same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, the third surface including a center, wherein two points on the periphery of the third surface and the center define a second plane and a second axial direction that is normal to the second plane and that is different from the first axial direction; and

a fourth array of in-phase current loops that are disposed adjacent to one another to define a fourth surface and to define a fourth virtual current loop at a periphery of the fourth surface that produces a same second direction virtual current that is opposite the same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, wherein the fourth surface is spaced apart from and at least partially overlaps the third surface in the second axial direction.

18. A system for wirelessly projecting power to wirelessly power microelectronic devices, the system comprising:

a plurality of first arrays of in-phase current loops, the first arrays of in-phase current loops being disposed adjacent to one another to define a first surface, each first array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent first arrays of in-phase current loops are not in-phase with one another, each first array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the first surface, such that current in adjacent portions of adjacent current loops in a first array flows in opposite directions, the first surface including a center, wherein two points on the periphery of the first surface and the center define a plane and an axial direction that is normal to the plane; and

a plurality of second arrays of in-phase current loops, the second arrays of in-phase current loops being disposed adjacent to one another to define a second surface, each second array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent second arrays of in-phase current loops are not in-phase with one another, each second array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the second surface, such that current in adjacent portions of adjacent current loops in a second array flows in opposite directions, wherein the first surface is spaced apart from and at least partially overlaps the second surface in the axial direction.

19. The system according to claim 18 wherein the virtual currents of adjacent arrays of in-phase current loops are of opposite phase from one another.

20. The system according to claim 18 wherein the plurality of first and second arrays of in-phase current loops each comprises four arrays of current loops that are arranged in two rows and two columns, such that the virtual currents in the arrays in each row and each column are of opposite phase.

21. The system according to claim 18 wherein the plurality of first and second arrays of in-phase current loops each comprises four arrays of current loops that are arranged in two rows and two columns, such that the virtual currents in the arrays in each row and each column are 90°

out-of-phase from one another.

22. The system according to claim 20 wherein the two rows and two columns are two oblique rows and two oblique columns.

23. The system according to claim 21 wherein the two rows and two columns are two oblique rows and two oblique columns.

24. The system according to claim 18 wherein the plurality of first and second arrays of in-phase current loops each comprises a plurality of arrays of current loops that are arranged in a circle, such that the virtual currents in adjacent arrays in the circle are of opposite phase.

25. The system according to claim 18 wherein each array of in-phase loops is arranged to provide at least some reinforcement of an electromagnetic near field that is produced by the current loops in an array while producing at least some cancellation of a far field electromagnetic wave that is produced by the current loops in the array.

26. The system according to claim 25 wherein the plurality of arrays of in-phase current loops are arranged provide at least some further reinforcement of the electromagnetic near fields that are produced by the arrays of in-phase current loops and at least some further cancellation of the far field electromagnetic waves that are produced by the arrays of in-phase current loops.

27. The system according to claim 18 wherein at least one of the plurality of first and second arrays of in-phase current loops comprises an array of at least two wedge-shaped current loops, each having an outer portion and a pair of sides, the at least two wedge-shaped current loops being disposed adjacent to one another to define a surface such that currents in the outer portions are in-phase and current in adjacent sides of adjacent current loops are out-of-phase.

28. The system according to claim 18 wherein at least one of the plurality of first and second arrays of in-phase current loops comprises an array of at least two polygonal current loops, each having a plurality of sides, the at least two polygonal current loops being disposed adjacent to one another to define a surface, such that currents in the sides of the at least two polygonal loops that are adjacent the periphery of the surface are in-phase and current in adjacent sides of adjacent current loops are out-of-phase.

29. The system according to claim 18 wherein at least one of the plurality of first and second arrays of in-phase current loops comprises an array of spiral current loops.

30. The system according to claim 18 wherein each of the in-phase current loops is less than a quarter wavelength long.

31. The system according to claim 18 wherein at least one of the plurality of first and second arrays of in-phase current loops comprises an array of concentric current loops.

32. The system according to claim 18 wherein least one of the plurality of first and second arrays of in-phase current loops comprises an array of stacked current loops.

33. The system according to claim 18 further comprising a driver that drives the plurality of first and second arrays of current loops at 13.56 MHz to thereby wirelessly project power.

34. The system according to claim 18 wherein the plurality of first and second arrays of in-phase current loops is arranged to provide at least some reinforcement of an electromagnetic near field that is produced by the current loops while producing at least some cancellation of a far field electromagnetic wave that is produced by the current loops.

35. The system according to claim 18 wherein the plurality of first and second arrays of in-phase current loops are of same size.

36. The system according to claim 18 wherein the first surface is spaced apart from and completely overlaps the second surface in the axial direction.

37. The system according to claim 35 wherein the first surface is spaced apart from and completely overlaps the second surface in the axial direction.

38. The system according to claim 18 further comprising a receive antenna between overlapping portions of the first and second surfaces.

39. The system according to claim 38 wherein the receive antenna is midway between the overlapping portions of the first and second surfaces.

40. The system according to claim 39 wherein the receive antenna extends parallel to the overlapping portion of the first surface.

41. The system according to claim 18 further comprising:

a plurality of third arrays of in-phase current loops, the third arrays of in-phase current loops being disposed adjacent to one another to define a third surface, each third array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent third arrays of in-phase current loops are not in-phase with one another, each third array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the third surface, such that current in adjacent portions of adjacent current loops in a third array flows in opposite directions, wherein the third surface is spaced apart from the second surface, is opposite the first surface and at least partially overlaps the second surface in the axial direction.

42. The system according to claim 18 wherein the plane is a first plane and wherein the axial direction is a first axial direction, the system further comprising:

a plurality of third arrays of in-phase current loops, the third arrays of in-phase current loops being disposed adjacent to one another to define a third surface, each third array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent third arrays of in-phase current loops are not in-phase with one another, each third array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the third surface, such that current in adjacent portions of adjacent current loops in a third array flows in opposite directions, the third surface including a center, wherein two points on the periphery of the third surface and the center define a second plane and a second axial direction that is normal to the second plane and that is different from the first axial direction; and

a plurality of fourth arrays of in-phase current loops, the fourth arrays of in-phase current loops being disposed adjacent to one another to define a fourth surface, each fourth array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent fourth arrays of in-phase current loops are not in-phase with one another, each fourth array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the fourth surface, such that current in adjacent portions of adjacent current loops in a fourth array flows in opposite directions, wherein the third surface is spaced apart from and at least partially overlaps the fourth surface in the second axial direction.

43. A method for wirelessly projecting power to wirelessly power microelectronic devices, the method comprising the steps of:

applying current to a first array of in-phase current loops that are disposed adjacent to one another to define a first surface and to define a first virtual current loop at a periphery of the first surface that produces a same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, the first surface including a center, wherein two points on the periphery of the first surface and the center define a plane and an axial direction that is normal to the plane; and

applying current to a second array of in-phase current loops that are disposed adjacent to one another to define a second surface and to define a second virtual current loop at a periphery of the second surface that produces a same second direction virtual current that is opposite the same first direction virtual current while current in adjacent portions of adjacent current loops flows in opposite directions, wherein the first surface is spaced apart from and at least partially overlaps the second surface in the axial direction.

44. A method for wirelessly projecting power to wirelessly power microelectronic devices, the method comprising the steps of:

applying current to a plurality of first arrays of in-phase current loops, the first arrays of in-phase current loops being disposed adjacent to one another to define a first surface, each first array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent first arrays of in-phase current loops are not in-phase with one another, each first array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the first surface, such that current in adjacent portions of adjacent current loops in a first array flows in opposite directions, the first surface including a center, wherein two points on the periphery of the first surface and the center define a plane and an axial direction that is normal to the plane; and

applying current to a plurality of second arrays of in-phase current loops, the second arrays of in-phase current loops being disposed adjacent to one another to define a second surface, each second array of in-phase current loops defining a virtual current such that virtual currents of at least some adjacent second arrays of in-phase current loops are not in-phase with one another, each second array of in-phase current loops comprising a plurality of in-phase current loops that are disposed adjacent to one another in the second surface, such that current in adjacent portions of adjacent current loops in a second array flows in opposite directions, wherein the first surface is spaced apart from and at least partially overlaps the second surface in the axial direction.