Nowadays, the world is governed by electronical instruments. Several monitoring, communication tools, and consumer products emit electromagnetic radiations at high frequency (X- and Ku-band). To overcome limitations linked to malfunctioning of the electronic network, a solution given by combining conductive carbon nanoparticles and resin is stated. By multiscale simulations through finite element analysis software, in this thesis shielding effectiveness is computed for different samples. Once established material properties - electrical permittivity and magnetic permeability from the literature, electrical conductivity and layer thickness from experiments - validation of only-MWCNTs’ block is made. Second study concerns a multi-layered structure (MWCNT-PMMA-MWCNT): validation is obtained for 1-pass, 10-passes and 20-passes structure.