Electromagnetic Shielding Effectiveness of Layered Polymer Nanocomposites

Conducting polymer composite is an attractive option as electromagnetic shielding material for applications in aviation and defense sectors where weight is an important criterion. Conductivity at low filler loading can be achieved in conventional composites by using fillers of large aspect ratio and small particle size but the conductivity achieved is not high enough. Thus, the conventional filled conducting composites are not suitable for many of the shielding applications. A new type of conducting polymer composite has been developed—the silicone rubber (SR) composite layered with carbon nanofiber (CNF) wafers which showed excellent shielding capabilities. In this study, the shielding capabilities of the SR composites layered with CNF wafers are studied in the 2–18 GHz frequency range. The layered SR composites showed very good shielding effectiveness in the above frequency range as compared to the conventional composites. To understand the reason for the enhanced shielding effectiveness, the permittivity and permeability of the samples were measured as per the ASTM D5568 standard. The reflection and absorption losses were also computed from the S parameters obtained.