Dielectric Characteristics of E-glass-Polyester Composite Containing Conductive Carbon Black Powder

The electromagnetic (EM) absorption or shielding characteristics of a material is an important issue not only for military purposes but also for commercial use such as in radar, electric and telecommunication devices. Nowadays studies on investigating the radar absorbing structures (RAS) using fiber reinforced polymeric (FRP) composites are becoming a popular research field. Since carbon black is widely used for EM absorption applications, in this study, the dielectric properties of the E-glass-polyester composite containing conductive carbon black are measured with the free space method in the X-band frequency range. In order to describe the dielectric behavior of the anisotropic FRP composite containing carbon black, the quantitative analysis of the measured permittivity is performed with respect to the content of carbon black, and the two-dimensional tensor transformation equation for estimating its dielectric properties is modified. Finally, the modified tensor transformation equation for the FRP composite with lossy ingredient is suggested and experimentally verified.