Large band inductive antenna for contactless communication systems

• US 8,401,471 B2
• Filed: 11/05/2008
• Issued: 03/19/2013
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: Sala Sabate, Judit, Thomas, Thierry
• Primary Examiner(s): Milord, Marceau
• Application Number:
  US12/741,275
• Publication Number:
  US 20100297938A1
• Time in Patent Office: 1,595 Days
• Field of Search: 455/41.1, 455/41.2, 455/558, 455/575.5, 455/575.7
• US Class Current: 455/41.1
• 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 19/07779 the inductive antenna being a coil
• 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 5/378 Combination of fed elements with parasitic 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

Signal transmission and/or reception device, by contactless inductive coupling comprising at least one structure forming one or several antennas, said structure comprising a plurality of conducting links (102, 106) in at least two parallel and distinct planes, a first plurality of said conducting links forming a first conducting circuit (104, 204, 304, 404, 504, 604, 704) through which a current (I₁) will circulate, and a second plurality of said conducting links forms at least one second conducting circuit (108, 208, 308, 408, 508, 608, 708), distinct from said first circuit, and through which a current (I₂) will circulate, the links being arranged such that the coefficient coupling between pairs of said circuits is zero or at least less than 5% or less than 1%.

Claims

1. A device for transmission of signals by contactless inductive coupling comprising at least one structure forming one or several antennas, said structure comprising a set of at least first and second pluralities of conducting links, each plurality of conducting links forming a conducting circuit through which a current may circulate,

the conducting circuits being distinct such that the current circulating in each circuit may be different, the set of said conducting links being arranged such that there is a projection of the conducting links in the form of a first contour with a first shape, a second contour located inside the first contour and in the same plane and with a second shape homothetic with said first shape, and a plurality of segments connecting the first contour and the second contour.

2. The device according to claim 1, in which each conducting circuit is located in a distinct plane.

3. The device according to claim 1, in which said conducting links in a particular circuit are included in at least 2 distinct parallel planes.

4. The device according to claim 1, each conducting circuit comprising a sequence of conducting parts, each conducting part being formed from:

a first conducting link the projection of which forms a portion of said first contour,

a second conducting link the projection of which forms a transition segment between the first contour and the second contour,

a third conducting link the projection of which forms a portion of the second contour

a fourth conducting link the projection of which forms a transition segment between the second contour and the first contour.

5. The device according to claim 1, said conducting links being arranged such that the coefficient coupling between pairs of said circuits is zero or at least less than 5% or less than 1%.

6. The device according to claim 1, in which each circuit is arranged so as to form a resonant loop.

7. The device according to claim 1, said segments connecting the first contour and the second contour being located on straight lines passing through the homothetic centre of said contours.

8. The device according to claim 1, in which said first shape and said second shape are polygonal, or circular or elliptical.

9. The device according to claim 1, in which at least one of said conducting circuits comprises one or several passive components.

10. The device according to claim 1, said structure comprising three pluralities of conducting links forming three distinct conducting circuits.

11. The device according to claim 1, each circuit being coupled or connected to a generator.

12. The device according to claim 1, in which at least one of said conducting circuits is connected to a generator, and at least one other of said circuits is connected to a signal reception stage.

13. The device according to claim 1, in which one or several of said conducting circuits are connected to one or several generators, the device comprising at least one connection block between said conducting circuits and said generators, the connection block comprising at least one power divider module, and/or at least one phase shift module, and/or at least one impedance matching module.

14. The device according to claim 1, in which one or several of said circuits is (are) connected to one or several signal reception stages, the device comprising at least one connection block between said conducting circuits and said reception stages, the connection block comprising at least filter means and/or at least one impedance matching module.

15. An inductive coupling or contactless communication device between a reader and at least a mobile object comprising a signal transmission device according to claim 1.