The present invention provides an electromagnetic wave absorbing sheet which contains: conductive short fibers; and soft magnetic particles, each of which is covered by an insulating material.

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.

Provided is an electromagnetic wave shielding and absorbing molded article which has excellent shielding properties and absorbency for electromagnetic waves having a specific frequency. The electromagnetic wave shielding and absorbing molded article includes a thermoplastic resin composition including stainless steel fibers, and the content ratio of the stainless steel fibers in the molded article is from 0.5 to 20 mass %. The electromagnetic wave shielding and absorbing molded article has a thickness from 0.5 mm to 5 mm, and a shielding property of 10 dB or greater and an absorbency of 25% or greater for electromagnetic waves having any frequency in a frequency domain from 59 GHz to 100 GHz.

A metallic component including a metallic material and having a skin depth of greater than or equal to 1.0 m in a frequency range from 20-40 GHz, as calculated by:

[00001]$=\sqrt{\frac{2.Math.}{\left(2.Math..Math..Math.f\right).Math.\left({}_0.Math.{}_r\right)}}5.Math.0.Math.3.Math.\sqrt{\frac{}{{}_r.Math.f}}.$

In this equation, is skin depth in meters (m); is resistivity in ohm meter (.Math.m); f is frequency of an electromagnetic radiation in hertz (Hz); .sub.0 is permeability; and .sub.r is relative permeability of the metallic material. The metallic component may be a discrete metallic particle or a layer in a multilayer thin film.

A metallic component including NiCr and having a skin depth of greater than or equal to 1.0 m in a frequency range from 20-40 GHz, as calculated by:

[00001]$=\sqrt{\frac{2.Math..Math.}{\left(2.Math..Math..Math..Math.f\right).Math.\left({}_0.Math.{}_r\right)}}503.Math..Math.\sqrt{\frac{}{{}_r.Math.f}}.$

In this equation, is skin depth in meters (m); is resistivity in ohm meter (.Math.m); f is frequency of an electromagnetic radiation in hertz (Hz); .sub.0 is permeability; and .sub.r is relative permeability of the NiCr metallic material. The metallic component may be a discrete metallic particle or a layer in a multilayer thin film.

Disclosed are exemplary embodiments of patterned electromagnetic interference (EMI) mitigation materials (e.g., EMI absorbers, thermally-conductive EMI absorbers, etc.) including carbon nanotubes. The carbon nanotubes may comprise single-walled carbon nanotubes, multi-walled carbon nanotubes, and/or carbon nanostructures comprising a branched network of crosslinked carbon nanotube structures. For example, an EMI mitigation material may comprise a filled dielectric including a pattern of EMI absorbers. The filled dielectric comprises carbon nanotubes.

A high-frequency module includes a first board on which an electronic device is mounted, a second board on which at least wiring is formed, and a radio-wave absorber disposed between the first board and the second board. Multiple slits are formed in the radio-wave absorber.

A method to mitigate an antenna multipath, Rayleigh fading effect. The method includes coupling an antenna on top of a structure, wherein the structure is covered by a radio frequency (RF) radiation absorbing layer, wherein the structure has a shape such that any reflecting surface of the structure is perpendicular to an incoming RF signal. The method also includes directing the incoming RF signal towards the structure, wherein undesired direct or reflected RF signals are either absorbed by the RF radiation absorbing layer or deflected back to a source of the RF signal, thereby avoiding interference of the undesired RF signal with a desired RF signal aimed at the antenna.

An electro-optic window is provided, together with a method of manufacturing the window. The window (3) is made of a material substantially transparent to at least one of infra-red, visible and UV radiation and treated to have reduced RF/MICROWAVE transmission characteristics by the provision of a grid (1) set into at least one surface (2) thereof. The grid (1) is formed of a material selected to be either reflective or absorptive to RF/MICROWAVE radiation.

The dipole-resonator resistive absorber is a metamaterial absorber operating in the microwave regime. A single unit of the dipole-resonator resistive absorber includes a first rectangular conductive ring having a pair of first resistors mounted thereon and in electrical communication therewith, and a plurality of parallel linear arrays of second rectangular conductive rings, where each of the second rectangular conductive rings has a pair of second resistors mounted thereon and in electrical communication therewith. The first rectangular conductive ring is mounted above the plurality of parallel linear arrays of the second rectangular conductive rings, and this structure is backed by an electrically conductive layer. The single unit dipole-resonator resistive absorber may be expanded into an arrayed structure, forming a polarization-independent dipole-resonator resistive absorber.