Development of lightweight carbon nanotube-based epoxy nanocomposite shield for broadband electromagnetic interference shielding: estimating shielding effectiveness and experimental validation

Abstract

Lightweight carbon nanotube (CNT)-based epoxy nanocomposite shield with 0.5 mm thickness are fabricated at various CNT concentrations for broadband electromagnetic interference shielding in this work. The electromagnetic parameters of the samples measured using impedance spectroscopy are used to estimate shielding effectiveness in the X and Ku frequency bands using finite element-based method. The shielding effectiveness obtained using the finite element model at 2 wt.% CNT concentration in the X and Ku bands are 19 dB and 26 dB which agrees well with experimental results obtained using waveguide measurement which amounts to 20 dB and 27 dB, respectively. The finite element model developed for the estimation of shielding effectiveness provides promising results in both X and Ku bands which are experimentally validated. Shielding effectiveness of the prepared samples in the Ku band is superior to that in the X band. High values of shielding in both X and Ku bands qualify it as a good broadband shield with minimal thickness and less weight and cost. Absorption phenomenon dominates the shielding mechanism in both these bands due to the dielectric losses and the electron-rich skeletal structure of CNT. The dominance of absorption loss increases as the frequency shifts from X to Ku band qualifying the developed nanocomposite material as a good broadband shield covering both X and Ku bands.