THE GAIN IN SHIEDLING EFFECTIVENESS ACHIEVED BY SUPERPOSITION OF STAINLES-STEEL PLASMA COATED WOVEN FABRICS DOI: 10.35530/TT.2021.56 I.R. Radulescu 1 *, L. Surdu 1 , E. Visileanu 1 , I. Sandulache 1 , C. Morari 2 , B. Mitu 3 1National Research Development Institute for Textiles and Leather, Romania (E-mail: razvan.radulescu@incdtp.ro, lilioara.surdu@incdtp.ro, e.visileanu@incdtp.ro, irina.sandulache@incdtp.ro) 2 ICPE-CA – Bucharest, Romania (E-mail: cristian.morari@icpe-ca.ro) 3 INFLPR – Magurele, Romania (E-mail: bogdana.mitu@inflpr.ro) Abstract: Electromagnetic shielding based on textile fabrics is important in applications for ensuring proper work of electronic equipment and for protection of human’s health. Fibre-based materials include a good capability for a precise design of the physical and electric properties of the EM shields. There are two main methods to impart electroconductive properties to textile fabrics: insertion of conductive yarns into the fabric structure and coating with conductive layers. In our approach, both methods were applied: cotton woven fabrics with conductive yarns of stainless steel and silver, were coated by magnetron sputtering with stainless steel layers. Electromagnetic shielding effectiveness (EMSE) was determined by Transversal-Electric- Magnetic (TEM) cell measurement system, according to standard ASTM ES-07. Moreover, EMSE was determined for the superposition of the manufactured textile shields. The stainless-steel plasma coating improves EMSE with 20 dB in case of the fabrics with stainless steel yarns and with 15-17 dB in case of the fabrics with silver yarns, in the frequency range of 0.1-1000 MHz. By superposition of the plasma coated shields, the gain in EMSE achieved was of 6 dB for the fabrics with stainless steel yarns and of 5-8 dB for the fabrics with silver yarns, on the same frequency range. EMSE has significant higher values in case of the superposed 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. Keywords: fabrics, plasma coating, shielding, superposition 1. INTRODUCTION Textile shields are used today in numerous applications for ensuring the proper work of electronic equipment and to protect human’s health against non-ionizing radiation. The manufacturing of electromagnetic shields encompasses several solutions of fibre-based materials with electric conductive properties, and represents a niche domain with a lot of scientific contributions [1-4]. Main technological approaches to impart electric conductive properties to textile materials include insertion of conductive yarns into the fabric structure and coating with conductive layers [5]. In our approach, we propose textile woven fabrics with both inserted conductive yarns and plasma conductive coating. The inserted conductive yarns are made of silver and stainless steel, while the magnetron sputtering deposition conducted to stainless steel coatings. The current paper aims to tackle the gain in shielding 348