Monte Carlo study on electromagnetic shielding properties of CNT nanocomposite foams in the X-band frequency range

This study introduces a sandwich structure model and employs the Monte Carlo (MC) technique to investigate the electromagnetic interference shielding effectiveness (EMI SE) of carbon nanotubes (CNT) nanocomposite foams. Firstly, a two-dimensional Voronoi diagram to simulate the composite foam structure is established. Then, by assuming that the edges of the polygon have a sandwich structure of insulator-conductor-insulator type, we evaluate the optical transmission matrix of the sandwich structure and calculate the transmission and reflection probabilities. Finally, the MC method is used to model the path of numerous light rays entering the composite foams. By statistically analyzing the electromagnetic fields of waves that are transmitted and reflected, we obtained the electromagnetic shielding properties of composite foams in the X-band frequency range. The results indicate that the foams amplify the multiple reflections of electromagnetic waves, thereby increasing its capacity to absorb electromagnetic energy. It is demonstrated that the variation of SE with CNT concentration matches well with the experimental findings. A detailed study is conducted on the effects of foam size, sandwich structure thickness and conductivity, and electromagnetic wave frequency on SE.