Electronic Entity Having a Magnetic Antenna

• US 20080211728A1
• Filed: 06/20/2006
• Published: 09/04/2008
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: IDEMIA France (Advent International Corporation)
• Original Assignee: Oberthur Technologies SA (Advent International Corporation)
• Inventors: Eray, Yves
• Granted Patent: US 7,830,324 B2
• Time in Patent Office: Days
• US Class Current: 343/788
• 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 1/22 by structural association with other equipment or articles
• 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 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

An electronic entity includes an electronic circuit (21) having at least one first terminal (22) and a second terminal (24) to which an antenna is connected. The antenna includes a conducting element (26) electrically connected to the first terminal (22) of the electronic circuit (21) and includes a resonator (28) insulated from the conducting element (26) at the antenna, electrically connected to the second terminal (24) of the electronic circuit (21) and coupled to the conducting element (26).

Claims

1. Electronic entity comprising an electronic circuit having at least a first terminal and a second terminal to which an antenna is connected,

characterized in that the antenna comprises a conductive member (6;

16;

26;

36) electrically connected to the first terminal of the electronic circuit and a resonator (8;

18;

28;

38) having a Q enabling amplification at the communication frequency of the electronic circuit, isolated from the conductive member (6;

16;

26;

36) at the level of the antenna, electrically connected to the second terminal of the electronic circuit, and coupled to the conductive member (6;

16;

26;

36).

2. Electronic entity according to claim 1, wherein the resonator (8;

18;

28;

38) is capacitively coupled to the conductive member (6;

16;

26;

36).

3. Electronic entity according to claim 2, wherein the capacitance of the conductive member is negligible compared to the coupling capacitance (C_C).

4. Electronic entity according to claim 2, wherein the resonator (8;

18;

28) comprises a turn facing the conductive member (6;

16;

26) over at least a portion of its perimeter.

5. Electronic entity according to claim 4, wherein the turn faces the conductive member (6;

16;

26) over virtually all of its perimeter.

6. Electronic entity according to claim 4, wherein the turn and the conductive member (6;

16;

26) are situated at a distance less than 0.5 mm over said perimeter portion.

7. Electronic entity according to claim 1, wherein the conductive member is formed by a turn portion.

8. Electronic entity according to claim 1, wherein the capacitance of the conductive member is negligible compared to the capacitance (C_R) of the resonator.

9. Electronic entity according to claim 1, wherein the inductance of the conductive member is negligible compared to the inductance (L_R) of the resonator.

10. Electronic entity according to claim 1, wherein the resonator (8;

18;

28;

38) takes the form of a conductive winding having at least one free end.

11. Electronic entity according to claim 10, wherein the resonator (28;

38) is connected to the second terminal by the end of the winding opposite the free end.

12. Electronic entity according to claim 10, wherein the conductive winding has two free ends.

13. Electronic entity according to claim 10, wherein said conductive winding comprises a plurality of turns.

14. Electronic entity according to claim 13, wherein the turns are separated two by two by a distance less than 0.5 mm.

15. Electronic entity according to claim 10, wherein the conductive member is inside the area defined by the resonator.

16. Electronic entity according to claim 1, wherein the resonator (8;

18;

28;

38) is inside the conductive member (6;

16;

26;

36).

17. Electronic entity according to claim 1, wherein the conductive member (6;

16;

26;

36) and the resonator (8;

18;

28;

38) are deposited on a common plane support.

18. Electronic entity according to claim 1, wherein the projection of the circuit formed by the antenna and the electronic circuit in a plane that is substantially parallel to that projection forms a line with no intersections and wherein the antenna comprises a winding (8;

18;

28;

38) that extends over strictly more than one turn.

19. Electronic entity according to claim 1, wherein the conductive member 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 member.

20. Electronic entity according to claim 19, wherein a median turn of the resonator is in line with the conductive member.

21. Electronic entity according to claim 1, wherein the resonant frequency of the resonator alone is not more than 10% greater than a communication frequency of the electronic circuit.

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

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

24. Electronic entity according to claim 23, wherein said communication frequency is from 1 MHz to 50 MHz.

25. Electronic entity according to claim 24, wherein the communication frequency is from 13 MHz to 15 MHz.

26. Electronic entity according to claim 25, wherein the resonant frequency of the resonator alone is from 13.6 MHz to 17 MHz.

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

28. Electronic entity according to claim 27, wherein the resonator (8;

18) comprises more than ten turns.

29. Electronic entity according to claim 27claim 1, wherein said exterior dimensions are less than 30 mm.

30. Pocket electronic entity according to claim 1.

31. Electronic entity according to claim 1, forming a microcircuit card.

32. Electronic entity according to claim 31, wherein the antenna extends over about half the area of the card.

33. Electronic entity according to claim 1, wherein the conductive member (16) forms a loop connected at both ends to the first terminal of the electronic circuit.

34. Electronic entity according to claim 1, wherein the end of the conductive member (6;

26;

36) opposite the first terminal of the electronic circuit is free.

35. Electronic entity according to claim 1, constituting an electronic identity document.