Electromagnetic wave absorbing structures including metal-coated fibers and methods of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10826190-B2
Application number	US-201615743710-A
Country	US
Kind code	B2
Filing date	Dec 1, 2016
Priority date	Mar 23, 2016
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

An electromagnetic wave absorber includes a first layer and a second layer disposed on the first layer. The first layer may include a first reinforcing fiber impregnated in a first matrix. The second layer may include a second reinforcing fiber impregnated in a second matrix. The second reinforcing fiber may be plated with a metal magnetic coating layer. The electromagnetic wave absorber may provide electromagnetic wave absorbing ability with a low uncertainty without reducing mechanical properties due to the metal magnetic coating layer.

First claim

What is claimed is:

1. A method of manufacturing an electromagnetic wave absorber, the method comprising:
determining a permittivity or a magnetic permeability according to a target frequency;
forming a metal magnetic coating layer on a surface of a second reinforcing fiber with an amount or a thickness corresponding to the permittivity or the magnetic permeability; and
impregnating the second reinforcing fiber in a second matrix, the second reinforcing fiber being plated with the metal magnetic coating layer,
wherein a second layer including the second reinforcing fiber is disposed on a first layer including a first reinforcing fiber impregnated in a first matrix, and
wherein the first matrix and the second matrix include a thermo-curable resin.

2. The method of claim 1 , wherein determining the permittivity or the magnetic permeability according to the target frequency includes generating combination of a real part and an imaginary part of an optimized permittivity according to the target frequency.

3. The method of claim 2 , wherein generating combination of the real part and the imaginary part of the optimized permittivity according to the target frequency uses Cole-Cole plot satisfying a non-reflection condition in the electromagnetic wave absorber.

4. The method of claim 1 , wherein forming the metal magnetic coating layer including dipping the reinforcing fiber in a metal salt aqueous solution including a metal salt compound and a reducing agent to perform an electroless plating coating.

5. The method of claim 4 , wherein the metal salt compound includes a nickel salt compound, and the reducing agent includes a phosphate salt or a boron compound.

6. The method of claim 5 , wherein the metal magnetic coating layer includes a nickel-phosphorous (Ni—P) alloy or a nickel-boron (Ni—B) alloy.

Assignees

• Agency Defense Dev

Inventors

• Kim Chun-Gon
• Nam Young-Woo
• Choi Jae-Hun

Classifications

• H01Q17/002

  using short elongated elements as dissipative material, e.g. metallic threads or flake-like particles · CPC title

• B32B38/08

  Impregnating · CPC title

• H05K9/009

  comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked · CPC title

• H01Q17/00 Primary

  Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems · CPC title

• H01Q17/005 Primary

  using woven or wound filaments; impregnated nets or clothes · CPC title