Design of Dual-Stopband and Polarization-Insensitive Active Frequency Selective Surface with a Ultra-Wide Tuning Range

In this paper, a widely tunable dual-stopband active frequency selective surface (AFSS) is proposed. The proposed design includes a periodic pattern printed on top of a thin substrate and a feeding network at the bottom. Varactor diodes are symmetrically installed on the top metallic layer. The simulation results indicate that the designed AFSS has two operating bands. The first stopband can be continuously tuned within the range of 0.97-6.88 GHz, while maintaining the stability of the second operating stopband. Additionally, the proposed AFSS exhibits excellent angular stability, polarization-insensitivity, miniaturization, and ultra-wideband tunability. It can be used to control electromagnetic wave propagation in various communication systems.