Adjusting Resonance Frequency by Adjusting Distributed Inter-Turn Capacity

• US 20080198078A1
• Filed: 08/25/2006
• Published: 08/21/2008
• Est. Priority Date: 09/02/2005
• Status: Active Grant

• Current Assignee: Thales DIS France SA
• Original Assignee: Gemplus (Thales SA)
• Inventors: Buyukkalender, Arek, Caruana, Jean-Paul, Seban, Frederick
• Granted Patent: US 7,928,918 B2
• Time in Patent Office: Days
• US Class Current: 343/745
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• 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 19/07781 the coil being fabricated in a winding process
• 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 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• 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 29/49016 Antenna or wave energy "plumbing" making

Abstract

The invention concerns a method for adjusting frequency tuning of a resonant circuit with turns having a regular spacing generating stray inter-turn capacity. The adjusting of the frequency tuning of the resonant circuit is performed, at the level of the stray inter-turn capacity, by varying the regular spacing of adjacent turns on at least one zone of the antenna. The invention uses this adjusting method for producing an adjusted antenna for a resonant circuit, the resonant circuit and a non-contact product. The invention concerns a device programmed for antenna production and/or definition.

Claims

1. A method for adjusting the frequency tuning of a resonant circuit comprising turns having a regular spacing generating a stray inter-turn capacity,

wherein said method includes a step of adjusting the stray inter-turn capacity by varying the regular spacing of adjacent turns of at least one partial zone of the antenna.

2. A method for producing an antenna adjusted for a resonant circuit, said antenna having at least one first zone comprising adjacent turns having a predetermined regular spacing,

wherein, on a second adjustment zone of the antenna, a spacing of adjacent turns is made which is distinct from the predetermined regular spacing of the turns.

3. A method for producing an antenna according to claim 2, wherein the adjustment zone of the stray capacity extends on a minimum part of its perimeter.

4. A method for producing an antenna according to claim 3, wherein the minimum part is lower than approximately a quarter of its perimeter.

5. A method for producing an antenna according to claim 2, wherein the diameter of the turns is between 200 μ

m and 300 μ

m.

6. A method for producing an antenna according to claim 2, wherein the turn spacing in the adjustment zone is greater than approximately 2 mm, the regular spacing of turns in the first zone being lower than approximately 1 mm.

7. A method for producing an antenna according to claim 6, wherein the inter-turn spacing in the adjustment zone is equal to approximately 3.5 mm for three outer turns and equal to approximately 2.5 mm for 3 inner turns.

8. A method for producing an antenna according to claim 2, wherein the adjustment zone is substantially inscribed in a rectangle of the order of 35×

12 mm, the antenna being inscribed in a zone of the order of 60×

35 mm.

9. A method for producing a resonant circuit, said resonant circuit comprising a capacity associated with an antenna,

wherein said capacity or a frequency tuning adjustment of the capacity is obtained by producing said antenna according to claim 2.

10. An adjusted antenna for a resonant circuit, said antenna having at least a first zone comprising turns having a predetermined regular spacing,

wherein the antenna comprises on at least a second partial zone, turns having an inter-turn spacing different from the predetermined regular spacing.

11. A resonant circuit comprising at least one capacity associated with one antenna, wherein said resonant circuit includes an antenna adjusted for a resonant circuit, said antenna having at least one first zone comprising adjacent turns having a predetermined regular spacing, and

a second zone having a spacing of adjacent turns which is distinct from the predetermined regular spacing of the turns.

12. A non-contact smart card comprising a resonant circuit with one antenna with an associated capacity, said antenna having at least one first zone comprising adjacent turns having a predetermined regular spacing, and

a second zone of the antenna having a spacing of adjacent turns which is distinct from the predetermined regular spacing of the turns.

13. A programmed device for the production and/or definition of an adjusted antenna for a resonant circuit, said antenna having at least a first zone comprising turns having a predetermined regular spacing and having a stray inter-turn capacity,

wherein said device includes processing means and a program configured so as to adjust the stray inter-turn capacity of the antenna by varying the regular spacing of adjacent turns on at least one partial zone of the antenna.