Transmitting magnetic field through metal chassis using fractal surfaces

• US 9,660,704 B2
• Filed: 12/28/2015
• Issued: 05/23/2017
• Est. Priority Date: 07/03/2012
• Status: Active Grant

• Current Assignee: Intel IP Corporation (Intel Corporation)
• Original Assignee: Intel IP Corporation (Intel Corporation)
• Inventors: Konanur, Anand S., Karacaoglu, Ulun, Yang, Songnan
• Primary Examiner(s): Trinh, Sonny
• Application Number:
  US14/981,618
• Publication Number:
  US 20160218777A1
• Time in Patent Office: 512 Days
• Field of Search: 455 411, 455 412, 455 39, 4555757, 340 101, 340 103, 343700 R, 343702, 343841
• CPC Class Codes: H01Q 1/2266 disposed inside the computer
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• 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 1/528 reducing the re-radiation of a support structure in a parabolic reflector antenna H01Q19/023
• 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: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/26 using coils

Abstract

Described herein are techniques related one or more systems, apparatuses, methods, etc. for reducing induced currents in a apparatus chassis. For example, a fractal slot is constructed in the apparatus chassis to reduce the induced currents, and enhance passage of magnetic fields through the apparatus chassis. In this example, the fractal slot may include a no-self loop fractal space filling curve shape to provide high impedance to the induced currents.

Claims

1. An apparatus comprising:

one or more processors;

a memory coupled to the one or more processors;

a near field communications (NFC) antenna coupled to the one or more processors wherein the NFC antenna includes a continuous multiple loop of coil that is integrated underneath a metal chassis of the apparatus; and

a conductive coating that is disposed in between the NFC antenna and the metal chassis, wherein at least one continuous fractal slot is constructed on the conductive coating and the metal chassis, wherein a direction of sliced slots or segments of the at least one continuous fractal slot is configured to be perpendicular to an assumed direction of an induced current on the conductive coating, wherein the assumed direction of the induced current on the conductive coating is opposite to a direction of an injected current on the continuous multiple loop of coil of the NFC antenna.

2. The apparatus as recited in claim 1, wherein the at least one continuous fractal slot defines an area that covers at least a perimeter of an outermost coil of the continuous multiple loop coil of the NFC antenna.

3. The apparatus as recited in claim 1, wherein the at least one continuous fractal slot is a no-self loop fractal space filling curve template that includes a Hilbert Curve, a Peano Curve, a Lebesque Curve, or an H-tree curve.

4. The apparatus as recited in claim 1, wherein the continuous multiple loop of coil forms a rectangular ring shaped—

NFC antenna.

5. The apparatus as recited in claim 4, wherein the assumed direction of the induced current on the conductive coating follows a pattern of the continuous multiple loop of coil of the rectangular ring shape—

NFC antenna.

6. The apparatus as recited in claim 1, wherein the sliced slots or segments form a geometric pattern configured to cut continuity of the induced current on the conductive coating.

7. The apparatus as recited in claim 1, wherein the continuous fractal slot is tiled into different quadrants of an area covering an approximate extent of electromagnetic fields that induce Eddy current to the conductive coating.

8. The apparatus as recited in claim 1, wherein the at least one continuous fractal slot includes an adjustable width to provide high impedance to Eddy current and frequency selectivity when the NFC antenna is operating in wireless fidelity (WiFi) signal frequency.

9. A method of reducing induced currents in an apparatus chassis comprising:

constructing a fractal slot on a conductive coating and the apparatus chassis, wherein a direction of sliced slots or segments of the fractal slot is configured to be perpendicular to an assumed direction of an induced current on the conductive coating, wherein the assumed direction of the induced current on the conductive coating is opposite to a direction of an injected current on a continuous multiple loop of coil of an near field communications (NFC) antenna, wherein the conductive coating is disposed in between the NFC antenna and the apparatus chassis;

radiating an electromagnetic field by the NFC antenna; and

providing high impedance to the currents induced by the electromagnetic field.

10. The method in claim 9, wherein the sliced slots or segments of the fractal slot is constructed on a metallic chassis or carbon-fiber chassis.

11. The method in claim 9, wherein the fractal slot defines an area that covers at least a perimeter of an outermost coil of the continuous multiple loop coil of the NFC antenna.

12. The method in claim 9, wherein the sliced slots or segments form a geometric pattern configured to cut continuity of the induced current on the conductive coating.

13. The method in claim 9, wherein the sliced slots or segments of the fractal slot include an adjustable width to provide a high impedance to the induced currents and to provide frequency selectivity when the NFC antenna is operating in a wireless fidelity (WiFi) signal frequency.

14. The method in claim 9, wherein the continuous multiple loop of coil forms a rectangular ring shaped—

NFC antenna.

15. The method in claim 14, wherein the assumed direction of the induced current on the conductive coating follows a pattern of the continuous multiple loop of coil of the rectangular ring shape—

NFC antenna.

16. The method in claim 9, wherein the fractal slot is tiled with another fractal slot to cover an area that includes approximate extent of an electromagnetic field that induces Eddy current to the conductive coating.

17. The method in claim 9, wherein the fractal slot is a no-self loop fractal space filling curve shape that includes a Hilbert Curve, a Peano Curve, a Lebesque Curve, or an H-tree curve.

18. The method in claim 9, wherein the induced current is an Eddy current that flows in opposite direction to the injected current in the NFC antenna.