EMI-Suppression from transmission lines
AssigneeGraham Magnetics Incorporated
InventorWilliam A. Manly
Life of this patent
Estimating the term…
Abstract
Absorptive shields for transmission lines, especially those tending to radiate electromagnetic wave lengths within a frequency range of from about 10.sup.6 to about 10.sup.10 hertz, especially 10.sup.7 to 10.sup.10 hertz. The shields are flexible materials filled with ferromagnetic, or ferrimagnetic, powders of selected particle size and distribution.
Claims48
A flexible transmission line of the type utilized to transmit electric current in the frequency range of 10.sup.6 to 10.sup.10 hertz and comprising
- (a) an electrical conductor
- (b) electrical insulation around said conductor
- (c) a metallic sheathing around said electrical insulation
- and a coating means placed around said sheathing to absorb electromagnetic radiation emanating from said line, in the range of 10.sup.6 to 10.sup.10 hertz, said means being formed of a shielding composition comprising ferromagnetic particles of above 20 microns in average maximum dimension in a resin matrix and said coating means being of such thickness that it has no substantial interference with the flexibility of said transmission line.
In electronic apparatus comprising a means to absorb the electromagnetic radiation in the range of 10.sup.6 hertz to 10.sup.9 hertz passing into or out of said apparatus, the improvement wherein said means to absorb is a thin coating comprising therein ferromagnetic metal particles having an average maximum dimension of from 38 micrometers to 50 micrometers.
A flexible, radiation-absorptive, sheet material comprising a flexible substrate and coated thereupon a flexible organic resin based coating comprising therein ferromagnetic metal particles having an av
A process for absorbing electromagnetic radiation in the frequency range of from about 10.sup.7 to 10.sup.10 hertz from a metal-shielded transmission line of the type transmitting at a frequency of from about 10.sup.7 to 10.sup.10 hertz, said process comprising the steps of overcoating said metal shield with a layer of a radiation-absorbing composition comprising small ferromagnetic particles dispersed in a resin matrix such that the volume conductivity of said composition is such that the skin depth factor is from about 0.2 to five times the thickness of said layer.
Dependencies are inferred from the claim text.