A permittivity regulating strategy to achieve high-performance electromagnetic wave absorbers with compatibility of impedance matching and energy conservation

Quan, Bin; Liang, Xiaohui; Xu, Guoyue; Cheng, Yan; Zhang, Yanan; Liu, Wei; Ji, Guangbin; Du, Youwei

doi:10.1039/c6nj03052a

Cited by 162 publications

(70 citation statements)

References 47 publications

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“…The minimum RL value of −67.1 dB could be obtained at 14.8 GHz, and the effective EA bandwidth could cover 5.92 GHz (12.08-18.00 GHz). The results fully demonstrated that Quan's [23] work acquired absorber with strong attenuation ability and suitable impedance matching simultaneously. Feng et al [37] constructed an rGO/ZnO composite through an in situ crystallization approach.…”

Section: Introductionmentioning

confidence: 66%

“…Carbon materials are representative absorbers, beneficial for their dielectric loss, but the high value of their conductivity from this kind material always makes their impedance mismatch [20][21][22]. According to a previous report [23], the calculated minimum reflection loss (RL) of graphene can hardly reach up to −10 dB. As a traditional absorber, ferromagnetic materials have been used since the First World War.…”

Section: Introductionmentioning

confidence: 99%

“…Summarily, it is a permittivity regulating strategy. Quan et al [23] prepared MoS 2 /rGO composites using an effective hydrothermal method. The minimum RL value of −67.1 dB could be obtained at 14.8 GHz, and the effective EA bandwidth could cover 5.92 GHz (12.08-18.00 GHz).…”

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

et al. 2020

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Currently, electromagnetic pollution management has gained much attention due to the various harmful effects on wildlife and human beings. Electromagnetic absorbers can convert energy from electromagnetic waves into thermal energy. Previous reports have demonstrated that reduced graphene oxide (rGO) makes progress in the electromagnetic absorption (EA) field. But the high value of permittivity of rGO always mismatches the impedance which results in more electromagnetic wave reflection on the surface. In this work, sandwich-like rGO/CuS/polypyrrole (PPy) nanoarchitectures have been synthesized by a facile two-step method. The experimental result has shown that a paraffin composite containing 10 wt.% of rGO/CuS/PPy could achieve an enhanced EA performance both in bandwidth and intensity. The minimum reflection loss (RL) value of −49.11 dB can be reached. Furthermore, the effective bandwidth can cover 4.88 GHz. The result shows that the as-prepared rGO/CuS/PPy nanoarchitectures will be a promising EA material.

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Section: Introductionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

et al. 2020

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“…It can be seen that the ε′ of the ICF rises slowly and then remains basically stable, while the ε′ of both 3D-ISF-I and 3D-ISF-II show downtrend. It is reported that the decrease of ε′ and the frequency dispersion effect are favorable for the microwave absorption [32]. With increment of the SiC layer thickness, the variation trend of ε′ of 3D-ISF-II is almost the same as that of 3D-ISF-I except a slight decrease.…”

Section: Electromagnetic Propertymentioning

confidence: 87%

Effect of SiC layer on microwave absorption properties of novel three-dimensional interconnected SiC foam with double-layer hollow skeleton

Li¹,

Mao²,

He³

et al. 2020

Mater. Res. Express

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To design a lightweight and high-performance absorber, this work introduced a novel threedimensional interconnected SiC foam with double-layer hollow skeleton (3D-ISF), which was prepared by depositing SiC, pyrolytic carbon, and SiC layer on interconnected carbon foam, followed by oxidation of carbon. SEM results showed the interconnected hollow structure had been successfully synthesized, which was beneficial for microwave absorbing efficiency, and numerous columnar SiC defects were observed and played a critical role in the microwave absorption properties. The electromagnetic performances of 3D-ISF-I and 3D-ISF-II were investigated in depth. With the increase of thickness of SiC layer, 3D-ISF-II exhibited a better microwave absorption property, which could be ascribed to the higher impedance matching ratio (Z r ) and attenuation constant (α). The optimum reflection loss value of 3D-ISF-II could reach −45.649 dB while that of 3D-ISF-I was just −32.070 dB. There is no doubt that the prepared materials have tunable microwave absorbing properties, which can promote the development of SiC-based absorbing materials to a certain extent. Finally, it was confirmed that the Z r played a dominant role in 3D-ISF, which provided practical guidance for the design of porous materials.

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“…They are the impedance matching, which requires permittivity and permeability of the material to be nearly equal and the other is energy conservation which requires the microwave absorbers to undergo strong propagation losses. The attenuation constant (α) gives the extent of propagation losses in the shield . According to transmission line theory, the integral attenuation loss ability of microwave absorbers can be given by,

true α = \frac{\sqrt{2} π f}{c} \times \sqrt{(μ " ϵ " - μ^{^{'}} ϵ^{^{'}}) + \sqrt{{(μ " ϵ " - μ^{^{'}} ϵ^{^{'}})}^{2} + {(μ^{'} ϵ " - μ " ϵ^{'})}^{2}}}

…”

Section: Effect Of Alloy/ Mwnt Heterostructure Particles On Electromamentioning

confidence: 99%

Magnetic Alloy‐MWNT Heterostructure as Efficient Electromagnetic Wave Suppressors in Soft Nanocomposites

2017

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FeNi (iron‐nickel) alloy particles were coated with MWNTs (Multiwalled carbon nanotubes) using simple ball milling technique at various alloy to MWNT ratios. These hybrid heterostructure were then dispersed in PVDF/TPU (Polyvinylidene fluoride/ Thermoplastic polyurethane) blends to develop flexible composite materials that can shield electromagnetic (EM) radiations. These alloy particles coated with MWNT localise mostly in the TPU phase of the binary blends. The shielding effectiveness (SE) measurements obtained from the scattering parameters reveal that for a particular ratio of FeNi/MWNT (3:1), the SE was the highest (‐35.7 dB) among the different composites studied here and manifested in improved microwave absorption in the blends. The absorption driven shielding is due to various polarization in the shield, thereby increasing the dielectric loss. It was observed that these MWNT wrapped magnetic alloy particles shielded the incoming EM radiations more effectively as compared to only MWNTs or only alloy particles. The soft nanocomposites designed here absorb up to 95 % of the incoming EM radiations. The lowest skin depth and highest specific EMI (Electromagnetic interference) shielding attained was 1.4 mm and −20.5 dB cm2 g−1 respectively for composites containing FeNi/MWNT‐ 3:1. The attenuation constant derived from different parameters of these blends were also analysed in order to develop a multi‐layered structure, having absorption‐multiple reflection‐absorption pathways. This was used to assess the effect of different layers and their sequence in the multi‐layered structure on final EM wave attenuation. Interestingly, multi‐layered architecture with a similar thickness showed three‐fold increase in the total shielding as compared to their bulk counterpart.

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A permittivity regulating strategy to achieve high-performance electromagnetic wave absorbers with compatibility of impedance matching and energy conservation

Abstract: With the variation of permittivity, MoS2/rGO composites with a broad frequency bandwidth and strong absorbing performance can be obtained due to their optimal compatibility of impedance matching and attenuation loss ability.

Cited by 162 publications

References 47 publications

Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

Effect of SiC layer on microwave absorption properties of novel three-dimensional interconnected SiC foam with double-layer hollow skeleton

Magnetic Alloy‐MWNT Heterostructure as Efficient Electromagnetic Wave Suppressors in Soft Nanocomposites

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