Contactless device with miniaturized antenna

• US 8,231,061 B2
• Filed: 02/23/2010
• Issued: 07/31/2012
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Icashe Incorporated
• Original Assignee: Tyfone Incorporated
• Inventors: Narendra, Siva G., Tadepalli, Prabhakar
• Primary Examiner(s): Frech, Karl D
• Application Number:
  US12/710,560
• Publication Number:
  US 20100213265A1
• Time in Patent Office: 889 Days
• Field of Search: 235/375, 235/492, 235/487, 235/488
• US Class Current: 235/492
• 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: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• 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 1/243 with built-in antennas
• 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

A contactless device includes a miniaturized antenna. The antenna includes an inductive coupling element that presents a field coupling surface area to couple to a magnetic field. The inductive element may be made of layers where conductive loops are formed parallel to the layers or perpendicular to the layers. When conductive loops are formed perpendicular to the layers, the effective field coupling surface area is increased. The inductive element is positioned on an outside edge of a memory card compatible device with the field coupling surface area perpendicular to the card.

Claims

1. An inductive element comprising:

a bottom surface; and

a plurality of layers substantially parallel to the bottom surface, the plurality of layers including a combination of electrically conductive material and electrically insulating material such that when bonded together the plurality of layers form at least one conductive coil having a field coupling surface area substantially perpendicular to the bottom surface.

2. The inductive element of claim 1 further comprising bonding areas on the bottom surface.

3. The inductive element of claim 1 wherein the plurality of layers include magnetic material forming a magnetic core within the at least one conductive coil.

4. An electronic device comprising:

a circuit board with a memory card slot interface;

a contactless communications device affixed to the circuit board, the contactless communications device having an antenna port; and

an inductive element affixed to the circuit board and electrically coupled to the antenna port, the inductive element having a conductive coil with a field coupling surface area substantially perpendicular to the circuit board.

5. The electronic device of claim 4 wherein the inductive element comprises a multilayer surface-mount inductor.

6. The electronic device of claim 5 wherein the multilayer surface-mount inductor is formed with layers substantially parallel to the circuit board.

7. The electronic device of claim 5 wherein the multilayer surface-mount inductor is formed with layers substantially perpendicular to the circuit board.

8. The electronic device of claim 4 wherein the memory card slot interface comprises a Secure Digital (SD) compatible interface.

9. The electronic device of claim 4 wherein the memory card slot interface comprises a micro Secure Digital (SD) compatible interface.

10. The electronic device of claim 4 wherein the memory card slot interface comprises a mini Secure Digital (SD) compatible interface.

11. An apparatus comprising:

a memory card compatible substrate having at least one surface, an inner edge, and an outer edge opposite the inner edge;

electrical contacts on the at least one surface and situated along the inner edge; and

a conductive coil situated along the outer edge, the conductive coil having a field coupling surface area substantially perpendicular to the at least one surface.

12. The apparatus of claim 11 wherein:

the at least one surface includes a top surface and a bottom surface substantially parallel to each other; and

the electrical contacts are on the top surface, and the conductive coil is on the top surface.

13. The apparatus of claim 11 wherein:

the at least one surface includes a top surface and a bottom surface substantially parallel to each other; and

the electrical contacts are on the top surface, and the conductive coil is on the bottom surface.

14. The apparatus of claim 11 wherein the conductive coil comprises a multilayer surface-mount inductor.

15. The apparatus of claim 14 wherein the multilayer surface-mount inductor is formed with layers substantially parallel to the at least one surface.

16. The apparatus of claim 14 wherein the multilayer surface-mount inductor is formed with layers substantially perpendicular to the at least one surface.

17. An apparatus comprising:

a memory card compatible substrate having at least one surface, an inner edge, and an outer edge opposite the inner edge;

electrical contacts on the at least one surface and situated along the inner edge; and

a three dimensional conductive coil situated along the outer edge;

wherein the apparatus has a micro secure digital (microSD) form factor, and wherein the three dimensional conductive coil has a field coupling surface area substantially perpendicular to the at least one surface of the memory card.