Miniaturized dual-band loaded frequency selective surface with narrow band spacing

In this paper, a novel miniaturized dual-band loaded frequency selective surface (FSS) with narrow band spacing is presented, in which each periodic cell consists of metallic patches connected with lumped inductors and capacitively loaded square loop aperture resonator printed on either side of a dielectric substrate. This structure provides two narrow and closely separated passbands with a distinct null, and an equivalent circuit model is given for analyzing its filter mechanism. The simulated transmission coefficients by CST Microwave Studio (MWS) indicate that the proposed FSS is insensitive to polarization and incident direction of the illuminated wave. A prototype is designed and fabricated for demonstration. Good agreement between the simulated and measured transmission coefficients is obtained, indicating the validity of the proposed design strategies.