Adjusting resonance frequency by adjusting distributed inter-turn capacity

• US 7,928,918 B2
• Filed: 08/25/2006
• Issued: 04/19/2011
• Est. Priority Date: 09/02/2005
• Status: Active Grant

• Current Assignee: Thales DIS France SA (Thales SA)
• Original Assignee: Gemalto SA (Thales SA)
• Inventors: Buyukkalender, Arek, Seban, Frédérick, Caruana, Jean-Paul
• Primary Examiner(s): Ho; Tan
• Application Number:
  US12/065,289
• Publication Number:
  US 20080198078A1
• Time in Patent Office: 1,698 Days
• Field of Search: 343/895, 343/745, 343/749, 235/492, 235/493
• 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 frequency tuning of a resonant circuit, the resonant circuit comprising a plurality of adjacent turns having a regular spacing that generate a stray inter-turn capacity, the plurality of adjacent turns defining a turns region, the method includes the steps of:

determining spacing of one or more adjacent turns in a sub-region of the turns region to attain a stray inter-turn capacity associated with a specified frequency of the resonant circuit; and

adjusting the stray inter-turn capacity by varying the regular spacing of the one or more adjacent turns in the sub-region of the turns region based on the determined spacing.

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

determining spacing of two or more adjacent turns in a second adjustment zone to attain a stray inter-turn capacity associated with a specified frequency of the resonant circuit,

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

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

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

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

m and 300 μ

m.

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

7. A method for producing the 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 three inner turns.

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

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

35 mm.

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

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

10. A method for producing the antenna according to claim 2, wherein the turns form a sequence of adjacent turns including a first turn and a last turn of the sequence such that a spacing associated with one pair of the adjacent turns, which does not include the first turn or the last turn of the sequence, has a spacing that is largest among spacings of the adjacent turns of the sequence.

11. A method for producing the antenna according to claim 2, further including producing a first resonant circuit prior to the adjusting of the stray inter-turn capacity for a subsequent batch of resonant circuits for a production order of the batch of resonant circuits.

12. 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, the turns having an inter-turn spacing different from the predetermined regular spacing,

wherein the turns form a sequence of adjacent turns including a first turn and a last turn of the sequence such that a spacing associated with one pair of the adjacent turns, which does not include the first turn or the last turn in the sequence, has a spacing that is largest among spacings of the adjacent turns of the sequence.

13. A resonant circuit comprising at least one capacity associated with an antenna, wherein said resonant circuit includes said antenna adjusted for the 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 the adjacent turns which is distinct from the predetermined regular spacing of the adjacent turns,

wherein the adjacent turns form a sequence of the adjacent turns including a first turn and a last turn of the sequence such that a spacing associated with one pair of the adjacent turns, which does not include the first turn or the last turn in the sequence, has a spacing that is largest among spacings of the adjacent turns of the sequence.

14. A non-contact smart card comprising a resonant circuit with an antenna having 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 adjacent turns of the first zone,

wherein the adjacent turns form a sequence of the adjacent turns including a first turn and a last turn of the sequence such that a spacing associated with one pair of the adjacent turns, which does not include the first turn or the last turn in the sequence, has a spacing that is largest among spacings of the adjacent turns of the sequence.

15. 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 programmed 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 to generate the resonant circuit of a desired resonant frequency based on a stray inter-turn capacity deviation associated with the varied regular spacing.