Design, Parametric Analysis, and Experimental Validation of a Screen-Printed Flexible Band-Stop Frequency Selective Surface

This study presents the design, simulation, fabrication, and experimental validation of a ring-shaped frequency-selective surface (FSS) applied onto textile using conductive polyurethane-based paint. The FSS was modeled in CST Studio Suite and optimized to achieve strong electromagnetic attenuation through a reflective band-stop mechanism in the 2–8 GHz frequency range. Simulation results revealed a resonance dip in the transmission coefficient (S21) at approximately 6.00 GHz, with a suppression level of −28 dB and a −10 dB bandwidth of approximately 1.7 GHz. The corresponding reflection coefficient (S11) was measured at approximately −3 dB, indicating dominant reflection and partial absorption (~50%), consistent with reflective band-stop filter behavior. A prototype was fabricated via screen printing the conductive paint onto a 150 mm × 150 mm textile substrate. Experimental measurements using a vector network analyzer (VNA) confirmed the band-stop performance and showed good agreement with the simulations. The proposed hybrid structure effectively integrates the electromagnetic functionality of metamaterials with the flexibility of textiles, making it suitable for applications such as electromagnetic shielding, stealth technology, and wearable electronics. The fabrication technique offers a scalable, low-cost solution for large-area, flexible, and conformal electromagnetic surfaces.