Electromagnetic Interference Shielding Analysis of Conducting Composites in Near- and Far-Field Region

The main objective of this paper is to develop a conducting composite sheet for coating of various electronic devices to provide effective electromagnetic interference (EMI) shielding in medical and defence application in near- and far-field region. Here, we utilize the dielectric properties of styrene acrylonitrile (SAN) copolymer and graphite (Gr) conducting composites in radio frequency ranges (10 MHz-1 GHz) for calculating EMI shielding properties. The SAN-Gr conducting composite sheets were prepared by mechanical mixing and the hot compression mold technique. The SAN-Gr conducting composites exhibited high dielectric constants (ε'), high dissipation factors (tan δ), and high ac conductivities (σ) in radio frequency regions. The main advantage of these composites incorporates their lightweight and low cost. The absorption loss (A), reflection loss (R), rereflection correction factor (C), and electromagnetic interference shielding effectiveness of the SAN-Gr conducting composite sheets were evaluated theoretically using a', tan δ, and σ for near- and far-field region. For electromagnetic compatibility in near- and far-field region (electric field, magnetic field, and plane wave), the adequate shielding effectiveness in the frequency range of 10 MHz-1 GHz of the SAN-Gr conducting composites was obtained with addition of Gr content.