Coupling in and to RFID smart cards

• US 8,991,712 B2
• Filed: 08/30/2012
• Issued: 03/31/2015
• Est. Priority Date: 08/12/2010
• Status: Active Grant

• Current Assignee: AmaTech Group Limited (Paragon Group Limited)
• Original Assignee: Féinics AmaTech Teoranta (Paragon Group Limited)
• Inventors: Ummenhofer, Klaus, Finn, David
• Primary Examiner(s): Haupt, Kristy A
• Application Number:
  US13/600,140
• Publication Number:
  US 20130075477A1
• Time in Patent Office: 943 Days
• Field of Search: 235/492
• US Class Current: 235/492
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: G06K 19/07794 the record carrier comprising a booster or auxiliary antenna in addition to the antenna connected directly to the integrated circuit
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• 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 1/2283 mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package
• 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: Y10T 29/49018 with other electrical component

Abstract

A data carrier such as a smart card comprising an antenna module (AM) and a booster antenna (BA). The booster antenna (BA) has an outer winding (OW) and an inner winding (IW), each of which has an inner end (IE) and an outer end (OE). A coupler coil (CC) is provided, connecting the outer end (OE, b) of the outer winding (OW) and the inner end (IE, e) of the inner winding (IW). The inner end (IE, a) of the outer winding (OW) and the outer end (OE, f) of the inner winding (IW) are left un-connected (free floating). The coupler coil (CC) may have a clockwise (CW) or counter-clockwise (CCW) sense which is the same as or opposite to the sense (CW or CCW) of the outer and inner windings. Various configurations of booster antennas (BA) are disclosed.

Claims

1. A data carrier component comprising:

a substrate (CB) having at least one surface and a periphery; and

a booster antenna (BA) disposed on at least one surface of the substrate (CB) and extending around the periphery of the substrate (CB);

wherein the booster antenna (BA) comprises an outer winding (OW) having an outer end (b) and an inner end (a) and an inner winding (IW) having an outer end (f) and an inner end (e); and

a coupler coil (CC) disposed on the card body (CB) and having two ends (c, d), one of which is connected with the outer winding (OW), the other of which is connected with the inner winding (IW);

characterized in that;

the one end (c) of the coupler coil (CC) is connected with the outer end (b) of the outer winding (OW);

the other end (d) of the coupler coil (CC) is connected with the inner end (e) of the inner winding (IW); and

the inner end (a) of the outer winding (OW) and the outer end (f) of the inner winding (IW) are left unconnected.

2. The data carrier component of claim 1, wherein:

the outer winding (OW) and the inner winding (IW) are connected in reverse phase with one another, via the coupler coil (CC).

3. The data carrier component of claim 1, wherein:

a sense for each of the outer winding (OW), inner winding (IW) or coupler coil (CC) is one of a first and a second opposite senses selected from clockwise (CW) or counter-clockwise (CCW);

at least one of the outer winding (OW) and inner winding (IW) exhibits the first of the two opposite senses; and

the coupler coil (CC) exhibits the second of the two opposite senses.

4. The data carrier component of claim 1, wherein:

the one end (c) of the coupler coil (CC) is its outer end (OE).

5. The data carrier component of claim 1, wherein:

the other end (d) of the coupler coil (CC) is its outer end (OE).

6. The data carrier component of claim 1, wherein:

the outer winding (OW) has a number of turns;

the inner winding (IW) has a number of turns; and

the coupler coil (CC) has a greater number of turns than at least one of the outer winding (OW) and the inner winding (IW).

7. The data carrier component of claim 1, wherein:

the outer winding (OW) has a first pitch;

the inner winding (IW) has a second pitch; and

the coupler coil (CC) has a third pitch which is not greater than at least one of the first and second pitches.

8. The data carrier component of claim 1, further comprising:

an antenna module (AM) comprising at least one chip or chip module (CM) and a module antenna (MA) disposed on the card body (CB) so that the module antenna (MA) inductively couples with the coupler coil (CC).

9. The data carrier component of claim 8, wherein:

the module antenna (MA) is disposed within the coupler coil (CC).

10. The data carrier component of claim 8, wherein:

the antenna module (AM) is disposed in a recess in the card body (CB) so that the module antenna (MA) is substantially coplanar with the coupler coil (CC).

11. A method of improving RF coupling between an external reader and a data carrier, the data carrier comprising:

providing a substrate (CB);

providing a booster antenna (BA) on the substrate (CB) comprising an outer winding (OW) and an inner winding (IW) disposed around the periphery of the substrate (CB), and a coupler coil (CC) connected to ends of the outer winding (OW) and inner winding (IW); and

providing an antenna module (AM) having an RFID chip (CM) and a module antenna (MA) on the substrate (CB);

characterized in that;

the booster antenna (BA) is configured as a quasi-dipole antenna with the outer winding (OW) and inner winding (IW) connected in reverse phase with one another.

12. The method of claim 11, wherein:

the outer winding (OW) has an outer end (b) and an inner end (a);

the inner winding (IW) has an outer end (f) and an inner end (e);

the inner end (e) of the inner winding (IW) is connected, via the coupler coil (CC), with the outer end (b) of the outer winding (OW); and

the inner end (a) of the outer winding (OW) and the outer end (f) of the inner winding (IW) are unconnected.

13. The method of claim 11, wherein:

the outer winding (OW), inner winding (IW) and coupler coil (CC) are formed as spirals, each exhibiting one of two opposite senses which are defined as clockwise (CW) and counter-clockwise (CCW);

the outer winding (OW) exhibits a first of the two senses;

the inner winding (IW) exhibits the first of the two senses; and

the coupler coil (CC) exhibits a second of the two senses which is opposite the first sense.

14. The method of claim 11, wherein:

the outer winding (OW) has a pitch;

the inner winding (IW) has a pitch which is substantially the same as the pitch of the outer winding; and

the coupler coil (CC) has a pitch which is not larger than the pitch of the outer winding (IW) and the inner winding (IW).

15. The method of claim 11, wherein:

the outer winding (OW) has a number of turns;

the inner winding (IW) has a number of turns which is substantially the same as the number of turns for the outer winding (OW); and

the coupler coil (CC) has a number of turns which is greater than the number of turns for the outer winding (IW) and the inner winding (IW).

16. Smart card comprising a card body (CB), a booster antenna (BA) in the card body (CB) and an antenna module (AM) disposed on the card body, characterized in that:

the booster antenna is disposed primarily at the periphery of the card body, and a portion of the booster antenna is routed towards an interior area of the card body, to achieve at least an approximately 90°

enclosure of the antenna module in a coupling area of the card body.

17. The smart card of claim 16, wherein:

the booster antenna comprises an outer winding (OW) and an inner winding (IW), and only the inner winding is routed towards the interior of the card body, the outer winding remaining substantially at the periphery of the card body.

18. The smart card of claim 16, further comprising at least one of:

ferrite disposed in the card body in the coupling area in and around the antenna module;

capacitive elements connected with free ends of the booster antenna.

19. The smart card of claim 16, wherein the booster antenna comprises an outer winding (OW) and an inner winding (IW), and further comprising:

an extension of the inner winding disposed near the coupling area.

20. The smart card of claim 16, wherein the booster antenna comprises:

a first booster antenna (BA-1) disposed on one side of the card body; and

a second booster antenna (BA-2) disposed on an opposite side of the card body.

21. A data carrier component comprising:

a substrate (CB) having at least one surface and a periphery; and

a booster antenna (BA) disposed on at least one surface of the substrate (CB) and extending around the periphery of the substrate (CB);

wherein the booster antenna (BA) comprises an outer winding (OW) having an outer end (b) and an inner end (a) and an inner winding (IW) having an outer end (f) and an inner end (e); and

a coupler coil (CC) disposed on the card body (CB) and having two ends (c, d), one of which is connected with the outer winding (OW), the other of which is connected with the inner winding (IW);

characterized in that;

the one end (c) of the coupler coil (CC) is connected with the outer end (b) of the outer winding (OW);

the other end (d) of the coupler coil (CC) is connected with the inner end (e) of the inner winding (IW); and

the inner end (a) of the outer winding (OW) and the outer end (f) of the inner winding (IW) are left unconnected;

wherein the data carrier further comprises at least one of the following features;

(i) a sense for each of the outer winding (OW), inner winding (IW) or coupler coil (CC) is one of a first and a second opposite senses selected from clockwise (CW) or counter-clockwise (CCW);

at least one of the outer winding (OW) and inner winding (IW) exhibits the first of the two opposite senses; and

the coupler coil (CC) exhibits the second of the two opposite senses;

(ii) the outer winding (OW) has a number of turns;

the inner winding (IW) has a number of turns; and

the coupler coil (CC) has a greater number of turns than at least one of the outer winding (OW) and the inner winding (IW);

(iii) the outer winding (OW) has a first pitch;

the inner winding (IW) has a second pitch; and

the coupler coil (CC) has a third pitch which is not greater than at least one of the first and second pitches.