Textile Embroidery FSS for Security Applications

This study presents the design and development of a flexible and lightweight Frequency Selective Surface (FSS) based on woven fabric, functioning as a band-stop filter with a center frequency of 3.9 GHz. FSS, composed of periodic arrays of conductive elements, has significant applications in defense, security, and communication systems due to its ability to manipulate electromagnetic wave propagation. The FSS was designed using CST EM full wave software and simulated within the WR-229 waveguide for fabrication simplicity. Two prototypes were developed: one with 35-micron thick copper tape and another with conductive thread embroidery on a woven cotton fabric with a dielectric constant of 1.83. The woven fabric, a plain weave of cotton fibers, measured 0.6 mm in thickness and 300 g/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The conductive yarn preferred for the design was Shieldex Statex 117 d/f17-2 ply. Design topology validated by fabrications and measurements having the results showing resonance at approximately −50 dB at 3.91 GHz in simulations, −36 dB at 3.83 GHz for the copper tape sample, and −20.09 dB at 3.82 GHz for the embroidered FSS. The study highlights the potential of textile-based FSS in modern communication and defense applications, offering advantages in terms of flexibility, durability, and ease of integration.