Electronic entity with magnetic antenna

• US 20090040116A1
• Filed: 05/24/2006
• Published: 02/12/2009
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Oberthur Technologies SA
• Original Assignee: Oberthur Card Systems, S.A. (Advent International Corporation)
• Inventors: Eray, Yves
• Granted Patent: US 8,698,690 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• 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: 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 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 7/005 with variable reactance for tuning the antenna

Abstract

The invention concerns an electronic entity comprising an electronic circuit and an antenna one part of which at least forms a conductive circuit connected to two ends of the electronic circuit. The projection of the circuit formed by the antenna and the electronic circuit in a plane which is substantially parallel thereto, forms an intersection-free line and the antenna includes a winding which extends over strictly more than one turn.

Claims

1. Electronic entity comprising an electronic circuit and an antenna at least a portion of which forms a conductive circuit connected to two ends of the electronic circuit,

characterized in that the projection of the circuit formed by the antenna and the electronic circuit in a plane that is substantially parallel to the latter forms a line with no intersections and in that the antenna comprises a winding that extends over strictly more than one turn.

2. Electronic entity according to claim 1, wherein the winding forms a plurality of turns.

3. Electronic entity according to claim 1, wherein the conductive circuit includes said winding.

4. Electronic entity according to claim 1, wherein the conductive circuit comprises a first strand and a second strand each forming a spiral, the first strand and the second strand being interlaced.

5. Electronic entity according to claim 4, wherein the second strand is essentially parallel at each point to the first strand.

6. Electronic entity according to claim 4, wherein the first strand and the second strand are separated by a distance of the same order of magnitude over all their length and essentially constant in each direction.

7. Electronic entity according to claim 5, wherein the first strand and the second strand are separated by at least 8 mm.

8. Electronic entity according to claim 5, wherein the first strand is connected to a first connecting land, wherein the second strand is connected to a second connecting land, and wherein the first strand and the second strand are connected by a connecting portion.

9. Electronic entity according to claim 8, wherein at least one of said connecting lands is situated in a central region of the antenna.

10. Electronic entity according to claim 1, wherein the antenna comprises a resonator coupled to the electrical conductor.

11. Electrical entity according to claim 10, wherein the electrical conductor is formed of a single turn.

12. Electronic entity according to claim 10, wherein the resonator is capacitively coupled to the conductive circuit.

13. Electronic entity according to claim 12, wherein the resonator comprises a turn facing the conductive circuit over at a least a portion of its perimeter.

14. Electronic entity according to claim 13, wherein the turn faces the conductive circuit over virtually all its perimeter.

15. Electronic entity according to claim 13, wherein the turn and the conductive circuit are at a distance less than 0.5 mm over said perimeter portion.

16. Electronic entity according to claim 10, wherein the resonator is formed of a conductive winding with free ends.

17. Electronic entity according to claim 16, wherein said conductive winding comprises a plurality of turns.

18. Electronic entity according to claim 17, wherein the turns are separated two by two by a distance less than 0.5 mm.

19. Electronic entity according to claim 16, wherein the conductive circuit is inside the resonator.

20. Electronic entity according to claim 10, wherein the resonator is inside the conductive circuit.

21. Electronic entity according to claim 10, wherein the conductive circuit and the resonator are deposited on the same flat support.

22. Electronic entity according to claim 10, wherein the conductive circuit is produced in a first plane, wherein the resonator is produced in a second plane different from the first plane, and wherein the resonator is in line with the conductive circuit.

23. Electronic entity according to claim 22, wherein a median turn of the resonator is in line with the conductive circuit.

24. Electronic entity according to claim 10, wherein the resonant frequency of the resonator alone is at most 10% higher than a communication frequency of the electronic circuit.

25. Electronic entity according to claim 10, wherein the resonant frequency of the resonator alone is between 13.6 MHz and 17 MHz.

26. Electronic entity according to claim 1, wherein the antenna is a magnetic antenna.

27. Electronic entity according to claim 1, wherein the electronic circuit operates at a communication frequency below 100 MHz.

28. Electronic entity according to claim 27, wherein said communication frequency is between 1 MHz and 50 MHz.

29. Electronic entity according to claim 28, wherein the communication frequency is between 13 MHz and 15 MHz.

30. Electronic entity according to claim 1, having exterior dimensions less than 100 mm.

31. Electronic entity according to claim 30, wherein the capacitance of the electronic circuit is greater than 100 pF.

32. Electronic entity according to claim 30, wherein said exterior dimensions are less than 30 mm.

33. Electronic entity according to claim 1, characterized in that it is a pocket electronic entity.

34. Electronic entity according to claim 1, characterized in that it is a microcircuit card.

35. Electronic entity according to claim 34, wherein the antenna extends over about half the area of the card.