Active frequency selective surface with two independent electromagnetic functions

In this paper., we present a novel active frequency selective surface (AFSS) with two independent functions. The function of frequency tuning for TM polarization and the function of electromagnetic switching for TE polarization can be achieved by controlling the varactor diodes and PIN diodes loaded on the top- and bottom-layer., respectively. A parallel feeding pattern is employed to reduce the negative impact of the bias network., which also guarantees the working reliability of the structure under damages of active devices and decreases the bias voltage for the components., especially for varactor diodes. In addition., equivalent circuit models for the AFSS have been constructed to analyze the working principle of the structure and verify the simulation results from the HFSS software.