Novel Multifunctional Reconfigurable Active Frequency Selective Surface

In this paper, a multifunctional active frequency selective surface (MAFSS) is presented based on the switching responses of active components. The proposed structure comprises periodic arrays of metallic patterns imprinted on both sides of an FR4 substrate on which p-i-n diodes are embedded with parallel feed networks. The novelty of the design lies in its multifunctional characteristics with independent control of the biasing states (ON/OFF) of the diodes mounted on opposite layers. This leads to four different working states (dual bandpass for OFF-OFF state, single-band absorber for OFF-ON state, single-bandpass for ON-OFF state, and reflector for ON-ON state) being facilitated by the proposed reconfigurable AFSS. Furthermore, the effects of the design parameters and active components on multifunctional responses are extensively analyzed by deriving equivalent circuit models. Even though the topology is polarization sensitive, multiple dividable working functions (transmission, absorption, and reflection) have been realized in single geometry, unlike the earlier reported designs. The proposed structure has also been fabricated, and the measured responses show reasonable agreement with the simulated results under normal incidence. An MAFSS with such diverse characteristics is an essential element for regulating electromagnetic wave propagation in manifold applications.