10 December 2012 Electromagnetic shielding efficiency in Ka-band: carbon foam versus epoxy/carbon nanotube composites
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Abstract
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, Polina P. Kuzhir, Alesia G. Paddubskaya, Alesia G. Paddubskaya, Mikhail V. Shuba, Mikhail V. Shuba, Sergey A. Maksimenko, Sergey A. Maksimenko, Alain Celzard, Alain Celzard, Vanessa Fierro, Vanessa Fierro, Gisele Amaral-Labat, Gisele Amaral-Labat, Antonio Pizzi, Antonio Pizzi, Gintaras Valušis, Gintaras Valušis, Jan Macutkevic, Jan Macutkevic, Maksim Ivanov, Maksim Ivanov, Juras Banys, Juras Banys, Silvia Bistarelli, Silvia Bistarelli, Antonino Cataldo, Antonino Cataldo, Matteo Mastrucci, Matteo Mastrucci, Federico Micciulla, Federico Micciulla, Immacolata Sacco, Immacolata Sacco, Eleonora Stefanutti, Eleonora Stefanutti, Stefano Bellucci, 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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