Enhancement of the Electromagnetic Wave Shielding Effectiveness by Geometry-Controlled Carbon Coils

Gi-Hwan Kang¹, Sung-Hoon Kim^1*, Saehyun Kim²

¹Center for Green Fusion Technology and Department of Engineering in Energy & Applied Chemistry, Silla University, Busan 617-736, Republic of Korea.
²Onnuri International Christian Academy, Yangsan, Kyungnam, 626-813, Republic of Korea.

DOI: 10.4236/msce.2015.31006                

Abstract

Carbon microcoils were deposited onto Al₂O₃ substrates using C₂H₂/H₂ as source gases and SF₆ as an incorporated additive gas in a thermal chemical vapor deposition system. At as-grown state, the carbon coils (d-CCs) show the diverse geometry. The geometry-controlled carbon microcoils (g-CMCs) could be obtained by manipulating the injection time of SF₆ in C₂H₂ source gas. The d-CCs with polyurethane (PU) composite (d-CC@PU) and the g-CMCs with PU composite (g-CMC@PU) were obtained by dispersing d-CCs and g-CMCs in PU, respectively. The electromagnetic wave shielding properties of d-CC@PU and g-CMC@PU composites were investigated in the frequency range of 0.25 - 4.0 GHz. The shielding effectiveness (SE) of d-CC@PU and g-CMC@PU composites were measured and discussed according to the weight percent of d-CCs and g-CMCs in the composites with the thickness of the composites layers. On the whole frequency range in this work, the SE of g-CMC@PU composites was higher than those of d-CC@PU composites, irrespective of the weight percent of carbon coils in the composites and the layer thickness. Furthermore, we confirmed that the absorption mechanism, instead of the reflection mechanism, seemed to play the critical role to shield the EMI for not only the g-CMC@PU composites but also the d-CC@PU composites.

Keywords

Carbon Coils, Electromagnetic Wave Interference, Shielding Effectiveness, Absorption Mechanism

Conflicts of Interest

The authors declare no conflicts of interest.

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