Analysis and Measurement of the Electromagnetic Shielding Efficiency of the Multi-Layered Carbon Fiber Composite Fabrics

Due to the individual behaviors and characteristics of composites, the usage areas of composites have expanded owing to the development of material science in recent years. In this study, electromagnetic shielding efficiency of carbon fiber composite fabrics, which are the one of the most widely used worldwide composite materials due to their electrical and mechanical properties, have been studied. Material samples were chosen as plain woven, twill woven and unidirectional polyacrylonitrile (PAN) based carbon fiber composites. The chosen carbon fiber fabric samples were investigated as both single layer and multilayer structure. Electromagnetic shielding measurements were carried out through vector network analyzer (VNA) in the frequency range of 3.3-4.9 GHz (S-C band). Single layer carbon fiber composite fabric samples were evaluated according to woven type, thickness and orientation. As a result of the evaluations, it was observed that different types of mesh structure caused a change in electromagnetic shielding efficiency. In order to investigate the effect of thickness for electromagnetic shielding efficiency, twill woven with the thicknesses of both 0.327 mm and 0.65 mm was measured. Electromagnetic shielding efficiency was increased while the thickness of the sample was increase, as it was expected. It was observed that the orientation did not affect significantly electromagnetic shielding efficiency of the plain woven and the twill woven samples. But, orientation was a substantial factor for the electromagnetic shielding efficiency of unidirectional structure. In multilayer structures, double and triple layered models of plain woven, twill woven and unidirectional woven fabrics, whose thicknesses are 0.327 mm, 0.327 mm and 0.48 mm respectively, were examined. The results showed that double and triple layered structures exhibited more than 80 dB and 90 dB electromagnetic shielding efficiency respectively.