Second Order Frequency Selective Surface Design Multi-functional at Two Bands

Abstract

Abstract This paper proposes an active frequency selective surface which furnishes three bands of higher order filtering characteristics. It controls multi-functional features, at two bands (centered at 2 GHz and 4 GHz), namely electromagnetic response and polarization of plane wave. Nine discrete filtering outputs are independently controlled through switching in bias supply to four PIN diodes embedded in two layers of AFSS unit cell. Two multifunctional bands hold stability upto 45◦ angles under all polarizations of wave. Passive band at around 5.9 GHz contributed by all the independent binary combinations exhibits stability upto 45◦ angles of TE wave only. The equivalent circuit method is used to explain and verify the designed structure. Finally, the AFSS structure is fabricated and reliability of the simulation results is verified through experiments.