Design and development of metal composite fabric assemblies for electromagnetic shielding

Abstract

Textile fabrics are known for their unique characteristics like drape, bending, shearing and supple besides being light in weight. Now-a-days the application of textiles is expanding from conventional textile structures used for clothing to advanced technical applications like personal and device protection to smart/intelligent textiles sensitive to external stimuli. This investigation aims to develop textile based soft barriers to suppress or arrest the invisible electromagnetic pollution causing hazards to electronic devices or human beings. Life is at risk if a mobile phone in the close vicinity is switched on during a fleet of flight. Use of mobile phones during the entire fleet is prohibited as per Govt. regulations . Pacemaker may fail due to EM interferences causing fatalities. This investigation pertains to developing metal composite textiles for shielding electromagnetic interferences. Electrically conductive metallic filaments, metal coated yarns, metal composite textile yarns and metallic fillers were utilized to develop fabrics for EMI shielding. Single jersey (SJ) knitted fabrics were developed from silver coated copper wire in bare form as well as in core spun structure. Core spun yarn was produced by short staple ring spinning and knitted fabric in two different loop lengths was produced there from. Fabrics embroidered with square loop pattern demonstrates resonance in reflectance in different frequency levels suggesting the possibility of developing spatial filters or frequency selective surfaces, however further studies in the Giga Hertz frequencies need to be carried out. Fabrics screen printed with aluminium and ferrous metallic fillers using acrylic binder showed lower SE values in concentration lower than threshold of 50% o.w.f. Double jersey fabrics showed maximum EM shielding in metal powder concentrations of 42 46%, with ferrous printed showing 1 dB and aluminium printed showing the highest SE of 12 dB. newline newline newline