RFID antenna modules and increasing coupling

• US 8,474,726 B2
• Filed: 08/08/2011
• Issued: 07/02/2013
• 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: Finn, David
• Primary Examiner(s): Haupt, Kristy A
• Application Number:
  US13/205,600
• Publication Number:
  US 20120038445A1
• Time in Patent Office: 694 Days
• Field of Search: 235/492
• US Class Current: 235/492
• CPC Class Codes: G06K 19/07783 the coil being planar
• 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 transponder with an antenna module having a chip module and an antenna; a booster antenna having a first antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end, and a second antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end; the inner end of the second antenna structure connected with the outer end of the first antenna structure. The antenna module may be positioned so that its antenna overlaps one of the first antenna structure or the second antenna structure. An antenna module having two additional antenna structures is disclosed. Methods of enhancing coupling are disclosed.

Claims

1. A transponder comprising:

an antenna module comprising a chip module and at least one antenna;

a booster antenna comprising a first antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end, and a second antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end;

the inner end of the second antenna structure is connected with the outer end of the first antenna structure; and

the outer end of the second antenna structure and the inner end of the first antenna structure are left unconnected.

2. The transponder of claim 1, wherein:

the first and second antenna structures are coupled in close proximity and voltages induced in the first and second antenna structures have opposite phase from one another.

3. The transponder of claim 1, wherein:

the antenna module is positioned so that its antenna overlaps one of the first antenna structure or the second antenna structure.

4. The transponder of claim 1, further comprising:

an additional antenna module having an antenna closely adjacent or overlapping the booster antenna.

5. The transponder of claim 1, wherein:

the first and second antenna structures are formed in the same layer as one another;

the second antenna structure is disposed within the first antenna structure.

6. The transponder of claim 1, wherein:

the first and second antenna structures are formed in layers overlying each other, substantially aligned with one another.

7. The transponder of claim 1, wherein:

the first and second antenna structures are each formed as flat coils of embedded wire, or other than embedded wire, having a number of turns and an overall length of approximately 1200 mm.

8. The transponder of claim 1, wherein:

the booster antenna has a pattern including at least one rectangular corner;

the antenna of the antenna module has a generally rectangular pattern; and

the antenna module is positioned so that at least two adjacent side edges of the antenna of the antenna module overlie or are close to one of the first antenna structure or the second antenna structure.

9. An antenna module for a transponder comprising:

a chip module;

a first antenna structure which is an antenna having two ends connected with the chip module;

a second antenna structure having an outer end and an inner end, one of which is connected with the first antenna structure, the other of which is left unconnected; and

a third antenna structure having an outer end and an inner end, one of which is connected with the first antenna structure, the other of which is left unconnected.

10. The antenna module of claim 9, wherein:

the inner end of one of the two stubs is connected with one end of the antenna, and the outer end of the other of the two stubs is connected with the other end of the antenna.

11. The antenna module of claim 9, wherein:

the first, second and third antenna structures are formed in a flat coil pattern having a number of turns, and are substantially identical with one another.

12. The antenna module of claim 9, wherein:

the first, second and third antenna structures are disposed substantially directly over one another.

13. The antenna module of claim 9, wherein:

the first, second and third antenna structures are formed by embedding wire.

14. The antenna module of claim 9, wherein:

the first, second and third antenna structures are formed other than by embedding wire.

15. The antenna module of claim 9, further comprising:

incorporating the antenna module in a secure document.

16. A method of coupling a transponder comprising an RFID chip module and an antenna to an external reader comprising:

providing an antenna module comprising a chip module and at least one antenna;

providing a booster antenna comprising a first antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end, and a second antenna structure in the form of a flat coil having a number of turns, an outer end and an inner end;

connecting the inner end of the second antenna structure with the outer end of the first antenna structure; and

leaving the outer end of the second antenna structure and the inner end of the first antenna structure unconnected.

17. The method of claim 16, further comprising:

positioning the antenna module so that its antenna overlaps one of the first antenna structure or the second antenna structure.