Electronic Beam Switching Using Graphene-Based Frequency Selective Surface

In this paper, graphene-based frequency selective structures (FSS) with tunable passband filtering characteristics are proposed. The FSS unit-cell element consists of four symmetrically rotated rectangular slots etched in a metallic sheet and placed on a square dielectric substrate. Graphene filled circular ring slot is etched around the rectangular slots to tune the performance of the FSS unit-cell element. The passband and stopband filtering properties of the graphene-based FSS structure are controlled by the graphene chemical potential. The proposed FSS unit-cell introduce wideband frequency tuning range from 1.7-2.6 THz for graphene biasing with 0.3eV to 2eV and resonant frequency of 3.5 THz for un-biased graphene. The gain of printed half-wave dipole is enhanced using 7 × 7 planar graphene-based FSS unit-cell elements placed as a ground plane. The distance between dipole antenna and the planar FSS array is optimized for maximum gain. Electronic beam switching is achieved by surrounding the dipole antenna with decagon FSS arrays of controlled filtering properties. The decagon side walls with biased FSS unit-cell elements have passband filtering property and the unbiased FSS unit-cell elements have stopband filtering property. Switching of single or multiple beams with reconfigurable beamwidth can be obtained easily with the decagon structure. The beamwidth of the switched beam is determined according to the number of the decagon side walls with biased FSS unit-cell elements.