Efficient adjustment of finite graphene scattering properties via magnetic-bias control for advanced beam manipulation

Abstract

In the present work, the scattering of an incident plane wave due to magnetically-biased graphene patches is thoroughly investigated at millimeter-wave and THz bands. Initially, the surface conductivity of graphene is evaluated at these spectral regions and a finite layer is placed perpendicular to the propagation of an incident plane wave. Then, the radar cross-section, at a plane normal to graphene, is numerically extracted and the anisotropic effects due to the magnetostatic bias Lorentz forces on electrons, reveal the influence of gyrotropy and magnetoplasmon excitation on the back-scattered wave. Specifically, the directivity of the latter is calculated as a function of the magnetostatic field considering a couple of electrostatic biases and frequencies. As expected, stronger fields are enabling graphene gyrotropic behaviour, while the propagating surface waves increase the edge effects of the finite sheet. Finally, the extracted results from the previous analyses are evaluated appropriately to design combinations of graphene patches, of different magnetic-bias fields in order to investigate the potential of advanced beam manipulation potential. The outcome of this part is promising since the variation of bias fields is able to adjust considerably the main-lobe direction of the back-scattered field. All numerical results are extracted via an accurate modification of the popular Finite-Difference Time-Domain scheme.