Radiation enhancement and decoupling

• US 8,684,270 B2
• Filed: 12/19/2007
• Issued: 04/01/2014
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Omni-Id Cayman Limited (Assa Abloy AB)
• Inventors: Lawrence, Christopher Robert, Brown, James Robert, Damerell, William Norman
• Primary Examiner(s): Frech, Karl D
• Application Number:
  US12/519,657
• Publication Number:
  US 20100230497A1
• Time in Patent Office: 2,295 Days
• Field of Search: 235/488, 235/487, 235/382
• US Class Current: 235/488
• CPC Class Codes: H01P 7/00 Resonators of the waveguide type
• 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

Abstract

Apparatus capable of enhancing an incident electric field to drive an electromagnetic tag (124) into operation, comprising a resonant dielectric cavity which extends out of a single plane defined between two conducting surfaces (102, 104, 106). The cavity may extend over two or more layers, and can adopt C or S shaped or spiral profiles.

Claims

1. Apparatus comprising a resonant dielectric cavity defined between conducting surfaces, adapted to enhance an electromagnetic field at the edge of one of said conducting surfaces, wherein said dielectric cavity is non-planar.

2. Apparatus according to claim 1, wherein said dielectric cavity comprises two or more dielectric layers defined between conducting walls.

3. Apparatus according to claim 2, wherein said layers are offset from one another.

4. Apparatus according to claim 2, wherein said layers are angled with respect to one another.

5. Apparatus according to claim 2, wherein said layers are joined at the ends thereof.

6. Apparatus according to claim 1, wherein said cavity has a unique path length.

7. Apparatus according to claim 6, wherein said dielectric cavity is substantially ‘

C shaped in cross section.

8. Apparatus according to claim 6, wherein said dielectric cavity is substantially ‘

S’

shaped in cross section.

9. Apparatus according to claim 6, wherein said dielectric cavity is substantially spiral shaped in cross section.

10. Apparatus according to claim 1, wherein said cavity has multiple path lengths.

11. A mounting component for an electronic device comprising a first dielectric layer arranged between first and second conductor layers, and a second dielectric layer arranged between said second conductor layer and a third conductor layer, said first and third conductor layers being electrically connected at one end, thereby defining a first dielectric connecting region, joining said first and second dielectric layers, wherein said mounting component is adapted to enhance an electromagnetic field at a mounting site at an open edge of said third conductor layer.

12. A mounting component according to claim 11, wherein said first and second conductor layers are electrically connected by an end wall, opposite said connecting region.

13. A mounting component according to claim 11, further comprising a third dielectric layer arranged between said third conductor layer and a fourth conductor layer, said second and third dielectric layer being joined by a second connecting region opposite said first connecting region.

14. A component according to claim 11, comprising an EM tag located at least partially in said area of field enhancement.

15. A component according to claim 14, wherein said tag is electrically isolated from said conductor layers or surfaces.

16. A component according to claim 14, wherein said tag is powered by differential capacitive coupling.

17. A component according to claim 14, wherein the EM tag is a low Q RFID tag.

18. A component according to claim 11, wherein the total thickness of the component or decoupler is less than λ

/4, or λ

/10, or λ

/300 or λ

/1000, where λ

is the intended wavelength of operation.

19. A component according to claim 11 wherein the total thickness of the component is 1 mm or less, or 500 μ

m or less, or 200 μ

m or less.

20. A component according to claim 11, wherein said electromagnetic field is enhanced by a factor greater than or equal to 50, 100, or 200.