Research On The Generation Of Vortex Radio Wave Based On Graphene

A vortex radio wave is an electromagnetic wave that carries orbital angular momentum(OAM).Theoretically,all OAM modes are orthogonal and they can be used independently for transmission of signals,so it has the potential to increase wireless communication capacity within a limited frequency band and to alleviate the problem of spectrum resources shortage.On the other hand,graphene has many extraordinary properties.Thus,it has been widely explored in many fields.In this thesis,we focus on the generation of THz vortex radio waves based on graphene.Major contributions are summarized as follows:1.A circular reflective surface model is proposed.By applying proper surface impedance in different sectors,the phase in the reflective waves can be modulated,thus,the incident plane waves are converted into vortex radio waves.2.A reconfigurable graphene reflectarray for generation of vortex radio waves is proposed.A graphene reflective cell is examined to demonstrate that the reflection coefficient can be controlled by changing the chemical potential and size of graphene patches.Then,the sectored circular reflective surface is realized through the graphene reflective cells and is excited with plane wave and a horn antenna,respectively.The graphene reflectarray proposed in this thesis is very promising for future applications in THz communication systems.