Devices to reduce electro-magnetic field radiation

• US 6,646,198 B2
• Filed: 01/04/2002
• Issued: 11/11/2003
• Est. Priority Date: 02/28/2001
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Maciver, Mark Alasdair, Knox, Andrew Ramsey
• Primary Examiner(s): Reichard, Dean A.
• Assistant Examiner(s): Nino, Adolfo
• Application Number:
  US09/683,479
• Publication Number:
  US 20020117314A1
• Time in Patent Office: 676 Days
• Field of Search: 174/35.R, 174/35.GC, 174/35.MS, 174/35.CE, 277/920, 336/84.R, 336/84.C, 336/84.M, 439/927, 361/800, 361/816, 361/818, 206/719
• US Class Current: 174/359
• 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 for reducing electromagnetic field radiation from an electrically conducting enclosure is disclosed. The apparatus comprises an electrically conducting element having two extremities and in which the electromagnetic field radiation induces a current, and an electrical resistance connected between the two extremities of the electrically conducting element so as to absorb the electromagnetic field radiation. In an embodiment to absorb electric field energy, the element is a substantially linear conducting element which absorbs electric field radiation and the electrical resistance has a direct electrical connection to a first extremity of the electrically conducting element. In an embodiment to absorb magnetic field energy, the element is a substantially circular conducting element which absorbs magnetic field radiation, each end of the electrical resistance having a direct connection to a respective extremity of the substantially circular conducting element.

Claims

1. Apparatus for reducing electromagnetic field radiation within an electrically conducting enclosure comprising:

an electrically conducting element having a first and a second extremity, wherein electromagnetic field radiation induces an electrical current in the electrically conducting element; and

,

an electrically resistant element having a first and a second end connected between the first and second extremities to absorb the electromagnetic field radiation.

2. Apparatus of claim 1, wherein the electrically conducting element is a substantially linear conducting element which absorbs electric field radiation, the first end of the electrically resistant element has a direct connection to the respective first extremity of the substantially linear conducting element.

3. Apparatus of claim 1, wherein the electrically conducting element is a substantially circular conducting element which absorbs magnetic field radiation, the first and second ends of the electrically resistant element having a direct connection to the respective first and second extremities of the substantially circular conducting element.

4. Apparatus of claim 3, wherein the substantially circular conducting element comprises multiple turns.

5. Apparatus of claim 1, wherein the electrically conducting element further comprises a high permittivity material located within a loop formed by the electrically conducting element and the electrically resistant element.

6. Apparatus of claim 1, wherein the electrically resistant element comprises a low conductivity layer.

7. Apparatus of claim 1, wherein the electrically resistant element comprises a surface mounted resistor.

8. Apparatus of claim 1, wherein the electrically resistant clement comprises ferrite.

9. Apparatus of claim 1, wherein the electrically conducting element is formed on a printed circuit board.

10. Apparatus of claim 9, wherein the printed circuit board comprises multiple layers and the electrically conducting element comprises multiple turns formed by connection of the multiple layers.