Contactless identification device

• US 7,520,440 B2
• Filed: 04/24/2007
• Issued: 04/21/2009
• Est. Priority Date: 12/10/2001
• Status: Expired due to Term

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Fractus SA
• Inventors: Puente Baliarda, Carles, Ortigosa Vallejo, Juan Ignacio
• Primary Examiner(s): St. Cyr; Daniel
• Application Number:
  US11/789,724
• Publication Number:
  US 20080006703A1
• Time in Patent Office: 728 Days
• Field of Search: 235/375, 235/487, 235/492, 235/494
• US Class Current: 235/492
• CPC Class Codes: G06K 19/045 the record carrier being of the non-contact type, e.g. RFID, and being specially adapted for attachment to a disc, e.g. a CD or DVD
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• 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 5/371 Branching current paths
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• 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

The invention relates to a contact-less identification device comprising a flat conducting structure as an electromagnetic sensor or transducer, and more particularly the invention relates to contactless cards, hybrid cards and radio operated electronic labels and tags. The electromagnetic sensor architecture according to the invention is suitable for all the applications where contactless or hybrid cards are of advantage: high volume paying and toll applications (public transportation, public sport events, person and good identification, access to controlled areas, control of shipment of goods, handling of luggage, product control in chain production environments), etc. The contact-less identification device according to the invention has had its performance enhanced by the use of space-filling techniques in the design of its electromagnetic sensor and by the use of a planar capacitor in conjunction with said flat conducting structure.

Claims

1. A contactless identification device comprising:

a capacitive element;

an inductive element connected in parallel with and on a common layer of the contactless identification device with the capacitive element;

wherein the inductive element comprises a conducting wire or strip defining a single-turn flat loop and two connection terminals;

wherein the capacitive element comprises a first conducting portion and a second conducting portion, the first and second conducting portions being coplanar, the first conducting portion being connected to a first connection terminal of the inductive element and the second conducting portion being connected to a second connection terminal of the inductive element;

an integrated circuit interoperably connected between the first and second connection terminals of the inductive element;

wherein at least part of the first conducting portion is shaped as a first curve comprising a plurality of connected segments; and

wherein the plurality of connected segments are spatially arranged so that no adjacent connected segments form a longer straight segment.

2. The contactless identification device of claim 1, wherein:

the first curve comprises at least ten segments; and

each of the plurality of connected segments is smaller than a tenth of a free-space operating wavelength.

3. The contactless identification device of claim 2, wherein the first curve is periodic along a fixed straight direction of space if and only if the period is defined by a non-periodic curve comprising at least ten connected segments and no pair of the adjacent connected segments defines a straight longer segment.

4. The contactless identification device of claim 1, wherein the at least part of the first conducting portion shaped as the first curve is the perimeter of the first conducting portion.

5. The contactless identification device of claim 1, wherein corners formed by each pair of adjacent connected segments are rounded or smoothed.

6. The contactless identification device of claim 1, wherein:

the first curve features a box-counting dimension larger than one;

the box-counting dimension is computed as the slope of a straight portion of a log-log graph; and

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph.

7. The contactless identification device of claim 6, wherein the box-counting dimension is larger than 1.2.

8. The contactless identification device of claim 6, wherein the box-counting dimension is larger than 1.5.

9. The contactless identification device of claim 1, wherein:

at least a part of the second conducting portion is shaped as a second curve comprising a plurality of connected segments; and

the plurality of connected segments of the second conducting portion are spatially arranged so that no pair of adjacent connected segments forms a longer straight segment.

10. The contactless identification device of claim 9, wherein the first curve and the second curve have the same number of connected segments.

11. The contactless identification device of claim 9, wherein:

the first curve and the second curve feature the same box-counting dimension;

the box-counting dimension is computed as the slope of the straight portion of a log-log graph;

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph; and

the box-counting dimension is larger than one.

12. The contactless identification device of claim 1, wherein the contactless identification device is selected from the group consisting of a contactless card, a hybrid card, a radio-operated electronic label, and a radio-operated electronic tag.

13. The contactless identification device of claim 1, wherein the contactless identification device is adapted for an application selected from the group consisting of high-volume payment, toll payment, person identification, access control to restricted areas, goods identification, shipment control, luggage handling, and product control in chain-production environments.

14. The contactless identification device of claim 1, wherein the two connection terminals are located in an internal region of the single-turn flat loop.

15. A contactless identification device comprising:

an integrated circuit;

an electromagnetic sensor configured as a dipole, the dipole comprising first and second conducting arms;

a capacitive element comprising first and second conducting surfaces;

wherein the electromagnetic sensor and the capacitive element are on a common layer of the contactless identification device;

wherein the first conducting surface is connected to an end of the first conducting arm and the second conducting surface is connected to an end of the second conducting arm;

wherein at least a portion of at least one of the first and second conducting arms is shaped as a curve comprising a plurality of connected segments; and

wherein the plurality of connected segments are spatially arranged so that no adjacent connected segments form a longer straight segment.

16. The contactless identification device of claim 15, wherein:

the curve comprises at least ten segments; and

each of the plurality of connected segments is smaller than a tenth of a free-space operating wavelength.

17. The contactless identification device of claim 16, wherein the curve is periodic along a fixed straight direction of space if and only if the period is defined by a non-periodic curve comprising at least ten connected segments and no pair of the adjacent connected segments defines a straight longer segment.

18. The contactless identification device of claim 15, wherein the at least a portion shaped as the curve is the perimeter of the first conducting arm.

19. The contactless identification device of claim 15, wherein corners formed by each pair of adjacent connected segments are rounded or smoothed.

20. The contactless identification device of claim 15, wherein:

the curve features a box-counting dimension larger than one;

the box-counting dimension is computed as the slope of a straight portion of a log-log graph; and

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph.

21. The contactless identification device of claim 20, wherein the box-counting dimension is larger than 1.2.

22. The contactless identification device of claim 20, wherein the box-counting dimension is larger than 1.5.

23. The contactless identification device of claim 15, wherein:

at least a portion of the first conducting arm is shaped as said curve;

at least a portion of the second conducting arm is shaped as a second curve comprising a plurality of connected segments; and

the plurality of connected segments of the second conducting surface are spatially arranged so that no pair of adjacent connected segments forms a longer straight segment.

24. The contactless identification device of claim 23, wherein the curve and the second curve have the same number of connected segments.

25. The contactless identification device of claim 23, wherein:

the curve and the second curve feature the same box-counting dimension;

the box-counting dimension is computed as the slope of the straight portion of a log-log graph;

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph; and

the box-counting dimension is larger than one.

26. The contactless identification device of claim 15, wherein the contactless identification device is selected from the group consisting of a contactless card, a hybrid card, a radio-operated electronic label, and a radio-operated electronic tag.

27. The contactless identification device of claim 15, wherein the contactless identification device is adapted for an application selected from the group consisting of high-volume payment, toll payment, person identification, access control to restricted areas, goods identification, shipment control, luggage handling, and product control in chain-production environments.

28. A contactless identification device comprising:

an electromagnetic sensor comprising a dipole, the dipole comprising first and second coplanar conducting arms, each of the first and second coplanar conducting arms comprising a connecting terminal;

an integrated circuit connected between the connecting terminals;

a conducting surface surrounding the integrated circuit and connected in parallel with and forming a parallel resonant circuit with the electromagnetic sensor;

wherein the electromagnetic sensor and the conducting surface are on a common layer of the contactless identification device;

wherein at least a portion of at least one of the first and second coplanar conducting arms is shaped as a curve comprising a plurality of connected segments;

wherein the plurality of connected segments are spatially arranged so that no adjacent connected segments form a longer straight segment.

29. The contactless identification device of claim 28, wherein the two coplanar conducting arms surround the conducting surface.

30. The contactless identification device of claim 28, wherein the two coplanar conducting arms are arranged symmetrically at opposite sides of the integrated circuit.

31. The contactless identification device of claim 28, wherein:

the curve comprises at least ten segments; and

each of the plurality of connected segments is smaller than a tenth of a free-space operating wavelength.

32. The contactless identification device of claim 31, wherein the curve is periodic along a fixed straight direction of space if and only if the period is defined by a non-periodic curve comprising at least ten connected segments and no pair of the adjacent connected segments defines a straight longer segment.

33. The contactless identification device of claim 28, wherein the at least a portion shaped as the curve is the perimeter of the first coplanar conducting arm.

34. The contactless identification device of claim 28, wherein corners formed by each pair of adjacent connected segments are rounded or smoothed.

35. The contactless identification device of claim 28, wherein:

the curve features a box-counting dimension larger than one;

the box-counting dimension is computed as the slope of a straight portion of a log-log graph; and

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph.

36. The contactless identification device of claim 35, wherein the box-counting dimension is larger than 1.2.

37. The contactless identification device of claim 35, wherein the box-counting dimension is larger than 1.5.

38. The contactless identification device of claim 28, wherein:

at least a portion of first conducting arm is shaped as said curve;

at least a portion of the second conducting arm is shaped as a second curve comprising a plurality of connected segments; and

the plurality of connected segments are spatially arranged so that no pair of adjacent connected segments forms a longer straight segment.

39. The contactless identification device of claim 38, wherein the curve and the second curve have the same number of connected segments.

40. The contactless identification device of claim 38, wherein:

the curve and the second curve feature the same box-counting dimension;

the box-counting dimension is computed as the slope of the straight portion of a log-log graph;

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph; and

the box-counting dimension is larger than one.

41. The contactless identification device of claim 28, wherein the contactless identification device is selected from the group consisting of a contactless card, a hybrid card, a radio-operated electronic label, and a radio-operated electronic tag.

42. The contactless identification device of claim 28, wherein the contactless identification device is adapted for an application selected from the group consisting of high-volume payment, toll payment, person identification, access control to restricted areas, goods identification, shipment control, luggage handling, and product control in chain-production environments.

43. A contactless identification system comprising:

a coupling device; and

at least one contactless identification device comprising;

an electromagnetic sensor comprising a first and a second conducting arm, each of the first and the second conducting arm having a connecting terminal connected thereto; and

an integrated circuit connected between the two connecting terminals;

wherein the size of the electromagnetic sensor is determined by a free-space operating wavelength so that the electromagnetic sensor is radiation-coupled to the coupling device;

wherein at least a portion of the electromagnetic sensor is shaped as a space-filling curve comprising at least ten connected segments; and

wherein each of the at least ten connected segments is smaller than a tenth of the free-space operating wavelength and is spatially arranged so that no adjacent connected segment forms a longer straight segment.

44. The contactless identification system of claim 43, wherein the at least a portion shaped as the space-filling first curve is the perimeter of the first conducting arm.

45. The contactless identification system of claim 43, wherein corners formed by each pair of adjacent connected segments are rounded or smoothed.

46. The contactless identification system of claim 43, wherein the space-filling curve is periodic along a fixed straight direction of space if and only if the period is defined by a non-periodic curve comprising at least ten connected segments and no pair of the adjacent connected segments defines a straight longer segment.

47. The contactless identification system of claim 43, wherein:

the space-filling curve features a box-counting dimension larger than one;

the box-counting dimension is computed as the slope of a straight portion of a log-log graph; and

the straight portion is defined as a straight segment over at least an octave of scales on the horizontal axis of the log-log graph.

48. The contactless identification system of claim 47, wherein the box-counting dimension is larger than 1.2.

49. The contactless identification system of claim 47, wherein the box-counting dimension is larger than 1.5.

50. The contactless identification system of claim 43, wherein the contactless identification device is selected from the group consisting of a contactless card, a hybrid card, a radio-operated electronic label, and a radio-operated electronic tag.

51. The contactless identification system of claim 43, wherein the contactless identification device is adapted for an application selected from the group consisting of high-volume payment, toll payment, person identification, access control to restricted areas, goods identification, shipment control, luggage handling, and product control in chain-production environments.