TITLE:
Enhancement of the Electromagnetic Wave Shielding Effectiveness by Geometry-Controlled Carbon Coils
AUTHORS:
Gi-Hwan Kang, Sung-Hoon Kim, Saehyun Kim
KEYWORDS:
Carbon Coils, Electromagnetic Wave Interference, Shielding Effectiveness, Absorption Mechanism
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.3 No.1,
January
20,
2015
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.