Electromagnetic enhancement and decoupling

• US 8,502,678 B2
• Filed: 08/14/2012
• Issued: 08/06/2013
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Omni-Id Cayman Limited (Assa Abloy AB)
• Inventors: Brown, James Robert, Lawrence, Christopher Robert
• Primary Examiner(s): Nguyen, Hung T.
• Application Number:
  US13/585,579
• Publication Number:
  US 20120305656A1
• Time in Patent Office: 357 Days
• Field of Search: 340/572.7, 340/572.1, 340/572.4, 340/572.8, 340/825.49, 340/825.69, 340/825.72, 340/10.1, 343/745, 343/751, 343/842, 343/851, 235/487, 235/492, 235/488
• US Class Current: 340/572.7
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00
• 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 19/07771 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
• CPC Class Codes: H01P 7/065 integrated in a substrate
• 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 1/38 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 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 13/08 Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines
• CPC Class Codes: H01Q 9/04 Resonant antennas
• CPC Class Codes: H05K 9/00 Screening of apparatus or components against electric or magnetic fields devices for absorbing radiation from an antenna H01Q17/00

Abstract

Apparatus and methods for providing a substantially surface independent tagging system are disclosed. A resonant dielectric cavity is defined between upper and lower conducting layers, and closed at one end by a conducting base portion. Incident radiation couples into the cavity and is resonantly enhanced. An electronic device or tag paced at the edge of the cavity experiences a high electric field strength on account of this enhancement and is driven into operation.

Claims

1. An electromagnetic radiation decoupler comprising:

a first cavity structure formed by a first conducting base portion connected to a first conducting side wall and a second conducting side wall, the first and second conducting side walls being spaced apart and substantially parallel and an open end opposite the first conducting side wall; and

a second cavity structure formed by a second conducting base portion connected to a third conducting side wall and a fourth conducting side wall, the third and fourth conducting side walls begin spaced apart and substantially parallel, and an open end opposite the second conducting side wall, wherein the second conducting side wall and fourth conducting side walls lie substantially on the same plane and wherein the first cavity structure and second cavity structure have adjacent open ends thereby forming a gap between the second conducting side wall and fourth conducting side wall.

2. The electromagnetic radiation decoupler of claim 1 wherein a dielectric material is located in a cavity structure selected from the group consisting of the first cavity structure, the second cavity structure or both the first cavity structure and the second cavity structure.

3. The electromagnetic radiation decoupler of claim 1 wherein the first conducting side wall extends to form the third conducting side wall.

4. The electromagnetic radiation decoupler of claim 1 wherein the gap is located about midway between the first conducting base portion and the second conducting base portion.

5. The electromagnetic radiation decoupler of claim 1 wherein an EM tag is mounted over the gap.

6. The electromagnetic radiation decoupler of claim 1 wherein an EM tag is mounted in the vicinity of the gap.

7. The electromagnetic radiation decoupler of claim 6 wherein a dielectric material is located in both of the first cavity structure and the second cavity structure and wherein the EM tag is mounted within the dielectric material.

8. The electromagnetic radiation decoupler of claim 1 including a spacer between the first cavity structure and the second cavity structure.

9. The electromagnetic radiation decoupler of claim 2 wherein a continuous dielectric material is located in both the first cavity structure and the second cavity structure.

10. A substantially surface independent EM tag comprising:

a first cavity structure formed by a first conducting base portion connected to a first conducting side wall and a second conducting side wall, the first and second conducting side walls being spaced apart and substantially parallel and an open end opposite the first conducting side wall;

a second cavity structure formed by a second conducting base portion connected to a third conducting side wall and a fourth conducting side wall, the third and fourth conducting side walls begin spaced apart and substantially parallel, and an open end opposite the second conducting side wall, wherein the second conducting side wall and fourth conducting side walls lie substantially on the same plane, wherein the first conducting side wall extends to form the third conducting side wall, and wherein the first cavity structure and second cavity structure have adjacent open ends thereby forming a gap between the second conducting side wall and fourth conducting side wall;

a continuous dielectric material located in the first cavity structure and the second cavity structure;

a gap between the second conducting side wall and third conducting side wall; and

an EM tag mounted in the vicinity of the gap.

11. The substantially surface independent EM tag of claim 10 wherein the EM tag is an RF tag.

12. The substantially surface independent EM tag of claim 11 wherein the RF tag is a low Q RF tag.