Lightweight Electromagnetic Interference Shielding Materials and Their Mechanisms

Zhang, Ling; Bi, Sheng; Liu, Ming

doi:10.5772/intechopen.82270

Cited by 17 publications

(18 citation statements)

References 38 publications

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“…However, such material is designed to protect against ionizing radiation and is designed to replace lead. Study [7] suggested a material based on carbon and aerogel. However, at acceptable protective properties, the mechanical properties of coatings are unsatisfactory.…”

Section: Introductionmentioning

confidence: 99%

Design of liquid composite materials for shielding electromagnetic fields

Glyva

Bakharev

Kasatkina

et al. 2021

EEJET

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This paper reports the principles of design and the examined protective properties of liquid materials for shielding the electric, magnetic, and electromagnetic fields over a wide frequency range. The materials were made on the basis of iron ore concentrate and a pigment additive, with water-dispersed and geopolymer paints used as a matrix. The tests of protective properties for the electrical and magnetic components of the electromagnetic field of industrial frequency showed that the electric field shielding coefficients at a concentration of the screening substance of 15−60 % (by weight) equaled 1.1−8.6; magnetic field – 1.2−5.3. The shielding coefficients of the material based on a water-dispersed paint are lower than those of a geopolymer one, which can be explained by the oxidation of an iron-containing component and a decrease in electrical conductivity. The shielding coefficients of the electromagnetic field with a frequency of 2.45 GHz are 1.2−7.9. The highest coefficients are inherent in the material with filler made of iron ore concentrate and titanium-containing pigment powder in a ratio of 1:1. To design materials with the required (predictable) protective properties, the relative magnetic, dielectric permeability of materials was calculated. It is shown that the obtained data are acceptably the same as the results from direct measurements of magnetic and dielectric permeability and could be used to calculate the wave resistance of the material and the predicted reflection coefficient of electromagnetic waves. Thus, there is reason to assert the need to build a database on the frequency dependence of effective magnetic and dielectric permeability in order to automate the design processes of composite materials with predefined protective properties.

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Section: Introductionmentioning

confidence: 99%

Design of liquid composite materials for shielding electromagnetic fields

Glyva

Bakharev

Kasatkina

et al. 2021

EEJET

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“…Hence, the benefits and the potential risks need to be accessed judiciously. The problem of protection against high energy microwaves EM radiation is typical due to high intensity reciprocal interference of electronic instruments working in close proximity [1][2][3][4][5][6]. Furthermore, uncontrolled long-term exposure to these radiations imposes hazardous consequences on living organism creating potential health risk even jeopardizing their life [7].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic shielding performance of copper and silver-plated hybrid yarn based multilayer fabrics in C & X band frequency range

Pandey¹,

Basu²,

Kumar³

2021

Journal of Industrial Textiles

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In the present study, a strategic designing of multilayer shield was planned to enhance the multiple reflection phenomenon to achieve maximum absorption properties in microwave frequency (C & X band) range. Multi-layer EMR shields were developed using pure cotton fabric and conductive woven fabrics, incorporated with copper- based & silver-plated hybrid yarn. First of all, single layer fabrics were produced in five variants, nomenclature as L1A (pure cotton) L1B, L1C (copper-based hybrid yarn), LS1B and LS1C (silver plated hybrid yarn). These five variants were used to prepare four sets of double & triple layer fabric. In both double and triple layer composition, L1A fabric (pure cotton) was used as top layer followed by B and C series fabrics, containing copper and silver-plated hybrid yarn. The EMSE performance in C and X band frequency range of single layer, double layer and triple layers in terms of scattering parameters S11(reflectance) & S21 (transmittance) in vertical and horizontal wave polarization was studied. It was found that number of layers, layer composition, orientation of metallic yarn, frequency and EM wave polarization have significant influence on overall electromagnetic shielding effectiveness.

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“…These materials are widely used in radar applications, for solving problems of increased electromagnetic environment pollution (via design of electromagnetic compatibility (EMC) materials and components), metamaterials, etc. Nanomaterials based on different forms of carbon (carbon black, activated carbon, carbon fibers, nanotubes, graphene) are the most important components in the development of EMM due to the successful combination of their properties (electrical conductivity, chemical stability, and lightness) . Among these materials, aerogels of multiwalled carbon nanotubes (MWCNTs) combine the unique mechanical, thermal, and electrical properties of nanotubes with specific characteristics of aerogels (low density, high porosity, and large surface area) .…”

Section: Introductionmentioning

confidence: 99%

“…Nanomaterials based on different forms of carbon (carbon black, activated carbon, carbon fibers, nanotubes, graphene) are the most important components in the development of EMM due to the successful combination of their properties (electrical conductivity, chemical stability, and lightness). [6][7][8][9][10] Among these materials, aerogels of multiwalled carbon nanotubes (MWCNTs) combine the unique mechanical, thermal, and electrical properties of nanotubes with specific characteristics of aerogels (low density, high porosity, and large surface area). [11] Due to the absence of a binder polymer, aerogels have the lowest density combined with high conductivity, which are unattainable for other classes of composites.…”

Section: Introductionmentioning

confidence: 99%

“…This model is semi-empirical since the experimentally determined polarizability of a spherical sample is used to estimate the electrophysical parameters of the aerogel environment. An experimental study of spherical aerogels in the gigahertz range (8)(9)(10)(11)(12) [30,31] showed that, despite the high conductivity of CNTs in the aerogel media and high density of their packages compared to the wavelength, effective parameters of aerogels noticeably differ from those of metals.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of Multiwalled Carbon Nanotube Aerogels with Quasi‐Optical Terahertz Beams

Dorofeev

Suslyaev

Мосеенков

et al. 2019

Physica Status Solidi (b)

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This article presents the measurements of the reflectance from a plane‐parallel aerogel sample formed by multiwalled carbon nanotubes (MWCNTs) in the terahertz range. With an increase in frequency from 100 GHz to 1.5 THz, the reflectance decreases by more than a factor of two. Based on the experimental data and the well‐known wire medium model formed by a three‐dimensional lattice of intersecting conductors, a model of a regular wire medium is constructed using MWCNTs with effective electrophysical characteristics equivalent to those of an irregular aerogel medium. This model reveals that a significant drop in the reflectance in the terahertz frequency range occurs because the plasma frequency of the equivalent medium is located here. The model allows estimating the properties of the aerogel environment in the frequency range extending up to 5 THz and with variations in the packing density of MWCNTs in aerogel. Estimates of the reflection, transmission, and absorption are presented for the case of normal incidence on a thin (submillimeter) layer of such a medium. The aerogel absorption at a given conductivity of CNTs is determined by their packing density.

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Lightweight Electromagnetic Interference Shielding Materials and Their Mechanisms

Cited by 17 publications

References 38 publications

Design of liquid composite materials for shielding electromagnetic fields

Design of liquid composite materials for shielding electromagnetic fields

Electromagnetic shielding performance of copper and silver-plated hybrid yarn based multilayer fabrics in C & X band frequency range

Interaction of Multiwalled Carbon Nanotube Aerogels with Quasi‐Optical Terahertz Beams

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