Electromagnetic radiation decoupler

• US 8,299,927 B2
• Filed: 06/25/2010
• Issued: 10/30/2012
• Est. Priority Date: 06/25/2005
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Omni-Id Cayman Limited (Assa Abloy AB)
• Inventors: Lawrence, Christopher Robert, Clarke, Paul Richard, Brown, James Robert, Damerell, William Norman
• Primary Examiner(s): La, Anh V
• Application Number:
  US12/823,299
• Publication Number:
  US 20110121079A1
• Time in Patent Office: 858 Days
• Field of Search: 3405721-5729, 340/10.1, 340/10.6, 235/488, 235/492, 235/487, 235380-385, 235/451
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/07 with integrated circuit chips
• CPC Class Codes: G06K 19/07722 the record carrier being multilayered, e.g. laminated sheets flat articles in general, see B32B37/00
• 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 19/0776 the adhering arrangement being a layer of adhesive, so that the record carrier can function as a sticker
• CPC Class Codes: G06K 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object

Abstract

An electromagnetic radiation decoupler for decoupling radiation in the wavelength range λ_min to λ_max. The decoupler has a first conductor layer in contact with a dielectric layer which comprises at least one area of absence and the thickness of the decoupler is less than λ_min/4n, where n is the refractive index of the dielectric. The dielectric layer may be sandwiched between two conductor layers, one of which has the structure described above. The invention is also directed to methods of using and various articles comprising such a decoupler.

Claims

1. A radiation decoupler for decoupling radiation from a conducting surface, said decoupler comprising:

a dielectric layer having a first surface and an opposing second surface;

a first conductor layer in contact with at least one dielectric layer surface, wherein the first conductor layer has at least one area of absence where the first conductor layer does not overlie the dielectric layer; and

an electronic device including an RF tag electrically connected to an antenna wherein the electronic device is located in the area of absence of the first conductor layer such that the electronic device antenna is electrically isolated from the first conductor layer, wherein the decoupler is adapted such that, in use, an electromagnetic field is enhanced in the vicinity of the area of absence of the first conductor layer.

2. The radiation decoupler of claim 1 wherein a second conductor layer contacts the dielectric layer second surface.

3. The radiation decoupler of claim 1 wherein the second conductor layer is the conducting surface from which radiation is decoupled.

4. The radiation decoupler of claim 1 wherein the RF tag is located at an edge of the dielectric layer.

5. The radiation decoupler of claim 1 wherein at least one edge of the dielectric layer forms at least a portion of the at least one area of absence.

6. The radiation decoupler of claim 1 wherein the at least one area of absence is located on the decoupler substantially at a point which corresponds to an increased dielectric field.

7. The radiation decoupler of claim 2 wherein the device antenna is electrically isolated from the second conductor layer.

8. The radiation decoupler of claim 2 wherein the length of the first conductor layer and second conductor layers are different.

9. The radiation decoupler of claim 1 including two or more electronic devices.

10. The radiation decoupler of claim 1 including a plurality of areas of absence.

11. The radiation decoupler of claim 1 wherein the RF tag is a low-Q tag.

12. The radiation decoupler of claim 1 wherein a spacer material layer separates the RF tag from the decoupler.

13. The radiation decoupler of claim 1 wherein a protective housing covers the decoupler.

14. The radiation decoupler of claim 1 where the RF tag has a resonant frequency and wherein the decoupler has a selected resonant frequency that substantially matches a resonant frequency of the RF tag.