Study of aperture size and its aspect ratio of conductive hybrid yarn woven fabric on electromagnetic shielding effectiveness

Abstract

The influence of aperture aspect ratio and its size on shielding effectiveness of grid fabric made up of carbon and stainless steel (SS) has been investigated in this article. The carbon and stainless steel based hybrid yarn was prepared by direct twisting machine and a woven grid fabric was prepared from the hybrid yarn by using CCI sample loom with varying warp and weft densities. The fabric samples were analyzed for shielding effectiveness (SE) in low frequency range (50 MHz to 1.5 GHz) using coaxial transmission line holder and a vector network analyzer. It has been observed that conductive hybrid yarns placed in one direction of the fabric showed polarization effect with the resonance peak at 0.65 GHz. The grid fabric having conductive yarns in both the directions showed larger attenuation than the unidirectional (UD) grid fabric. In addition, fabric made-up of carbon filaments showed higher attenuation level than that of SS filaments due to its larger conductivity. When the both carbon and stainless steel are introduced as hybrid yarn in the fabric, a maximum SE was observed. In addition, effect of orientation of fabric layers on SE has been investigated. The increase in number of fabric layers increased the SE to a certain frequency. The carbon UD fabrics with 0°/45° (or) 0°/45°/90° showed larger SE than the fabrics with other orientation angles. The similar behavior was observed for SS UD fabrics. The developed fabrics can be used as polarization attenuator, shielding mesh, etc.