Abstract-Electromagnetic properties of model vitreous carbon foams

• M. Letellier^a, 
• J. Macutkevic^b, 
• P. Kuzhir^c, d, 
• J. Banys^b, 
• V. Fierro^a, 
• A. Celzard^a, , 

• ^a Institut Jean Lamour, UMR CNRS – Université de Lorraine n°7198, ENSTIB, 27 rue Philippe Séguin, BP 21042, 88051, Epinal cedex 9, France
• ^b Faculty of Physics, Radiophysics Department, Vilnius University, Sauletekio 9/3, 10022, Vilnius, Lithuania
• ^c Institute for Nuclear Problems, Belarusian State University, 220030, Minsk, Belarus
• ^d Tomsk State University, 36, Lenin Avenue, Tomsk, 634050, Russia

http://www.sciencedirect.com/science/article/pii/S0008622317306589

This paper addresses the relationship between structural and electromagnetic (EM) properties of model vitreous carbon foams, i.e., presenting different porous structures in terms of bulk density, cell size and connectivity, while having the same composition and the same carbon texture. EM properties were investigated over a wide frequency range, from 20 Hz up to 250 THz. The bulk density is the main parameter controlling the EM behaviour up to ∼50 GHz, as no change was found by varying other structural parameters such as cell size or interconnectivity in such frequency range. At low frequency, foams behave similarly to metals and, when the density increases, the reflection increases and the absorption decreases. The behaviour changes above ∼50 GHz, absorption becoming the main mechanism. For cellular foams, transmission and reflection tend to be negligible in the infrared region, and behave like black bodies. However, reticulated foams present non-negligible transmission that increases with cell size. Resonance phenomena were observed for reticulated foams between about 0.2 and 3 THz. A simple model considering the fundamental mode TE₁₀ of a rectangular waveguide whose largest dimension was the average cell diameter was proposed to predict minima and maxima of these resonances.

Abstract-F Electromagnetic and thermal properties of three-dimensional printed multilayered nano-carbon/poly(lactic) acid structures

A. Paddubskaya1,2, N. Valynets1, P. Kuzhir1,3,a), K. Batrakov1, S. Maksimenko1,3, R. Kotsilkova4, H. Velichkova4, I. Petrova4, I. Biró5,b),K. Kertész6,c), G. I. Márk6,c), Z. E. Horváth6,c) and L. P. Biró6,c)


a) Author to whom correspondence should be addressed. Electronic mail: polina.kuzhir@gmail.com. Tel.: +375 17 200 7410.
b) URL: http://3dkivansag.blog.hu/
c) URL: http://www.nanotechnology.h
http://scitation.aip.org/content/aip/journal/jap/119/13/10.1063/1.4945576?TRACK=RSS

A new type of light-weight material produced by 3D printing consisting of nano-carbon doped polymer layer followed by a dielectric polymer layer is proposed. We performed temperature dependent characterization and measured the electromagnetic (EM) response of the samples in the GHz and THz range. The temperature dependent structuralcharacteristics, crystallization, and melting were observed to be strongly affected by the presence and the number of nano-carbon doped layers in the sandwich structure. The electromagnetic measurements show a great potential of such a type of periodic materialfor electromagnetic compatibility applications in microwave frequency range. Sandwich structurescontaining only two nano-carbon layers already become not transparent to the microwaves, giving an electromagnetic interference shielding efficiency at the level of 8–15 dB. A sandwich consisting of one nano-carbon doped and one polymer layer is opaque for THz radiation, because of 80% of absorption. These studies serve as a basis for design and realization of specific optimal geometries of meta-surface type with the 3D printing technique, in order to reach a high level of electromagnetic interference shielding performance for real world EM cloaking and EM ecology applications.