Fiber-based structures for electromagnetic shielding – comparison of different materials and textile structures

In this study, 32 different electro-conductive fabrics and seven different non-conductive fabrics were taken for an analysis of their electromagnetic shielding ability, electrical resistivity and air permeability. According to the present state of development of electromagnetic shielding textile structures, a diverse set of samples was selected, including stainless steel, copper, silver, aluminum, carbon and polypyrrole as a conductive component. The ASTM D4935 coaxial transmission line method was used to study the electromagnetic shielding and the ASTM D257 ring electrode method was used to evaluate the surface and volume electrical resistivity of all the samples. Air permeability was considered as an additional important parameter for the production of electromagnetic radiation protective fabrics designed for technical or clothing applications. It was confirmed that textile structures made of conventional textile fibers are transparent to an electromagnetic field. The electromagnetic shielding effectiveness of non-conductive samples is less than 0.2 dB regardless of material composition. On the other hand, the electromagnetic shielding effectiveness of electro-conductive samples containing different content and types of conductive component ranges from 1 to 79 dB at the high-frequency range, whereas the woven sample containing 75 wt% of staple metal fiber provides excellent shielding ability together with high air permeability. It was confirmed that, in particular, the surface resistivity can be used to predict the electromagnetic shielding ability of fabric samples due to a strong inverse relationship between these two parameters.