Electromagnetic interference shielding mechanisms of CNT/polymer composites

Al‐Saleh, Mohammed H.; Sundararaj, Uttandaraman

doi:10.1016/j.carbon.2009.02.030

Cited by 1,294 publications

(765 citation statements)

References 31 publications

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“…5). As the shape of the sheet greatly influences the SE [8], we designed a two-layered shielding sheet with four dome-shaped structures. In the center of the sheet we added another smaller dome-shaped structure to efficiently shield the area which experiences the most powerful electromagnetic waves.…”

Section: A Simulation Methodsmentioning

confidence: 99%

“…The second mechanism, absorption, is also an important factor in shielding electromagnetic waves. The effectiveness of absorption depends on the thickness of the shielding material [8]. The third mechanism, multiplereflection, can typically be ignored if the shielding material is thicker than the skin depth (the skin effect is the tendency of electromagnetic fields to be attenuated rapidly with depth inside a conductor, the level of which this happens to is called the "skin depth").…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of Novel Electromagnetic Shielding Sheets Using Carbon-Nanotube-Composite Paper

Oya

2014

e-J. Surf. Sci. Nanotechnol.

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We propose a new electromagnetic shielding (EMS) sheet that uses carbon nanotube (CNT)-composite paper. The electromagnetic environment in which electronic devices such as mobile phones and personal computers operate has become increasingly complex due to increased electromagnetic noise. This noise can cause unexpected behavior in electronic devices. Therefore, EMS sheets are required to shield devices from this noise. Carbon-nanotube composite paper has high electrical conductivity despite being a paper and does not deteriorate like metallic materials which are commonly used for EMS sheets. In this study, we aim to use CNT-composite paper to develop new EMS sheets that have a high shielding effectiveness (SE) (over 30 dB) at frequencies in the 0.1 MHz to 1 GHz range. To achieve this, we made test samples and measured their SE with the Kansai Electronic Industry Development Center (KEC) method. The first CNT-composite paper we developed achieved an SE of 20-50 dB from 0.1 MHz to 100 MHz. However, the SE was 16 dB in the GHz band. To increase the SE in this band, we designed and simulated many different shapes of shielding sheet which we then fabricated to measure their SE. We obtained positive results, indicating that a new shielding paper shape has a higher SE in the GHz band.

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Section: A Simulation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fabrication of Novel Electromagnetic Shielding Sheets Using Carbon-Nanotube-Composite Paper

Oya

2014

e-J. Surf. Sci. Nanotechnol.

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“…(S1)-(S3) in the Supporting Information [25]. These equations are valid when the thickness of the slab is greater than the skin depth (δ).…”

Section: Methodsmentioning

confidence: 99%

Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range

Crespo

González

Elías

et al. 2014

Phys. Status Solidi RRL

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CVD synthesised CNT flexible sponge with density lower than 0.02 g cm–3 has been found to serve as high performance EMI shielding material without the aid of any polymer infiltration or impregnation. Due to its extreme lightweight, the specific SE of the CNT‐sponge was found to be as high as 1100 dB cm3 g–1, having a total SE above 20 dB in the whole 1–18 GHz range, and being able to shield by absorption. The material is the best of our knowledge this specific SE value appears to be the highest reported hitherto. Improved EM absorbers should fulfil the synergic requirements of being low reflective and highly absorptive. In our CNT‐sponges this condition is not satisfied because, although their net absorption ability is strongly remarkable, their high electrical conductivity favours the wave to be reflected at the input interface. Therefore, this sponge material would have a great potential for microwave‐frequency applications that need negligible reflection and great absorption when combined in a multilayered structure that could prevent the wave to be reflected at the input interface. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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“…For a sheet of homogeneous conductive material (not a composite of a conductive filler and insulating matrix), reflection is the primary shielding mechanism. To shield by reflection, the material must have mobile charge carriers (electrons or holes) to interact with the incoming EM waves [11]. Absorption is the second important mechanism and it depends on the thickness of the shield.…”

Section: Electromagnetic Interference Shieldingmentioning

confidence: 99%

“…The first reflection of an EM wave from a conductive material surface should be distinguished from the multiple-reflection mechanism which is the re-reflection of the waves already reflected [11].…”

Section: Electromagnetic Interference Shieldingmentioning

confidence: 99%

Electrical Conductivity and Electromagnetic Shielding Effectiveness of Silicone Rubber Filled With Ferrite and Graphite Powders

Morari¹,

Balan²,

Pintea³

et al. 2011

PIER M

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Abstract-There is increasing interest in electromagnetic interference (EMI) shielding due to the serious electromagnetic environment pollution caused by the continuously increased use of the electrical products and electronic devices. Electrical conductivity and EMI shielding effectiveness (SE) of composite materials made from silicone rubber with carbon powder and ferrite powder have been studied in microwaves and terahertz frequency ranges and the results are presented in this paper. In microwaves range, samples with higher electrical conductivity show a small variation of shielding performance with frequency, whereas the performance of samples with lower conductivity falls away with increasing frequency. It is shown that the variation of attenuation with frequency relates to the conductivity of the material.

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Electromagnetic interference shielding mechanisms of CNT/polymer composites

Cited by 1,294 publications

References 31 publications

Fabrication of Novel Electromagnetic Shielding Sheets Using Carbon-Nanotube-Composite Paper

Fabrication of Novel Electromagnetic Shielding Sheets Using Carbon-Nanotube-Composite Paper

Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range

Electrical Conductivity and Electromagnetic Shielding Effectiveness of Silicone Rubber Filled With Ferrite and Graphite Powders

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