10 December 2012 Electromagnetic shielding efficiency in Ka-band: carbon foam versus epoxy/carbon nanotube composites
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The wide application of microwaves stimulates searching for new materials with high electrical conductivity and electromagnetic (EM) interference shielding effectiveness (SE). We conducted a comparative study of EM SE in K a -band demonstrated by ultra-light micro-structural porous carbon solids (carbon foams) of different bulk densities, 0.042 to 0.150  g/cm 3 , and conventional flexible epoxy resin filled with carbon nanotubes (CNTs) in small concentrations, 1.5 wt.%. Microwave probing of carbon foams showed that the transmission through a 2 mm-thick layer strongly decreases with decreasing the pore size up to the level of 0.6%, due to a rise of reflectance ability. At the same time, 1 mm thick epoxy/CNT composites showed EM attenuation on the level of only 66% to 37%. Calculating the high-frequency axial CNTs' polarizability on the basis of the idea of using CNT as transmission lines, we devised a strategy to improve the EM SE of CNT-based composites: because of the high EM screening of inner shells of multi-walled CNTs in the GHz range, it is effective to use either single-walled CNT or multi-walled CNTs with a relatively small number of walls (up to 15, i.e., those taking part in the EM interaction, if the CNT length is 20 μm).
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)
Polina P. Kuzhir, Alesia G. Paddubskaya, Mikhail V. Shuba, Sergey A. Maksimenko, Alain Celzard, Vanessa Fierro, Gisele Amaral-Labat, Antonio Pizzi, Gintaras Valušis, Jan Macutkevic, Maksim Ivanov, Juras Banys, Silvia Bistarelli, Antonino Cataldo, Matteo Mastrucci, Federico Micciulla, Immacolata Sacco, Eleonora Stefanutti, Stefano Bellucci, "Electromagnetic shielding efficiency in Ka-band: carbon foam versus epoxy/carbon nanotube composites," Journal of Nanophotonics 6(1), 061715 (10 December 2012). https://doi.org/10.1117/1.JNP.6.061715 . Submission:


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