Facile fabrication of a frequency-selective surface for terahertz communication applications

Next-generation communication devices require facile, conformable frequency-selective surfaces (FSS) operating in the sub-terahertz frequency range to modulate specific bandwidths with high angular stability. Here, we design a double-square-loop split-ring resonator (SRR) FSS pattern to study and modulate the frequency filtering by varying the SRR's composition and geometry. Numerical analysis revealed that varying the SRR width enabled a tunable frequency bandwidth with strong angular stability up to 65°. In addition, optimizing the SRR composition and thickness of the FSS tunes the shielding effectiveness at the strong bandstop regions. To experimentally realize the FSS, we employed facile single-step thermal evaporation to fabricate an FSS film on a flexible, low-loss polyimide substrate. The fabricated large-area FSS validated the numerical results and demonstrated excellent flexibility and shape conformability. This facile fabrication route and tunable SRR FSS pattern offer a practical platform for reconfigurable sub-terahertz FSS filters, with strong prospects for integration into future communication devices.