Graphene-FSS Hybrid Absorptive Structure With Amplitude/Frequency Dual-Modulated Passband

In this letter, a reconfigurable absorptive frequency selective surface (FSS) based on graphene sandwich structure (GSS) and varactor-tunable FSS is proposed. The frequency and amplitude of transmission window can be tuned continuously and independently by applying bias voltages to GSS and FSS, with absorption bands below and above the passband maintained. The feeding network is integrated with the GSS-FSS hybrid structure creatively, maintaining desirable responses and symmetry of the structure for dual-polarized functionality. Moreover, the transmission window can be turned off by controlling the polarity of the biasing voltages, rendering the rasorber with the switchable properties. In the absorber mode, absorptivity can be manipulated by varying the bias voltage of GSS. The measured results agree with the simulation results well, validating the desired dual-reconfigurability of our design.