THE GAIN IN SHIEDLING EFFECTIVENESS ACHIEVED BY SUPERPOSITION OF STAINLES-STEEL PLASMA COATED WOVEN FABRICS

Electromagnetic shielding based on textile fabrics is important in applications for ensuring properwork of electronic equipment and for protection of human’s health. Fibre-based materials include a goodcapability for a precise design of the physical and electric properties of the EM shields. There are two mainmethods to impart electroconductive properties to textile fabrics: insertion of conductive yarns into the fabricstructure and coating with conductive layers. In our approach, both methods were applied: cotton wovenfabrics with conductive yarns of stainless steel and silver, were coated by magnetron sputtering with stainlesssteel layers. Electromagnetic shielding effectiveness (EMSE) was determined by Transversal-Electric-Magnetic (TEM) cell measurement system, according to standard ASTM ES-07. Moreover, EMSE wasdetermined for the superposition of the manufactured textile shields. The stainless-steel plasma coatingimproves EMSE with 20 dB in case of the fabrics with stainless steel yarns and with 15-17 dB in case of thefabrics with silver yarns, in the frequency range of 0.1-1000 MHz. By superposition of the plasma coatedshields, the gain in EMSE achieved was of 6 dB for the fabrics with stainless steel yarns and of 5-8 dB for thefabrics with silver yarns, on the same frequency range. EMSE has significant higher values in case of thesuperposed shields with silver yarns and stainless-steel coating for the frequency domain of 100-1000 MHz,due to the higher thickness and the significant contribution of the multiple reflection term.