Electrically and Magnetically Biased Graphene-Based Cylindrical Waveguides: Analysis and Applications as Reconfigurable Antennas

The propagation of surface waves along electrically and magnetically biased graphene-based cylindrical waveguides (GCWs) is investigated in detail. Analytical dispersion equations are derived for several GCW geometries, considering the presence of an inner metallic core and multiple (coaxial-like) graphene layers. The proposed formulation reveals a fundamental connection between surface plasmons found in GCWs/carbon nanotubes and planar graphene structures. Numerical results confirm the higher confinement of modes supported by GCWs compared with their planar counterparts, while keeping a similar level of losses. The proposed structure is applied to develop plasmonic reconfigurable dipole antennas in the low THz band, which provide higher radiation efficiency than current graphene-based radiators, without requiring the presence of bulky lenses. We envision that the proposed GCWs may find application in reconfigurable THz transceivers, near-field application, wireless interconnects, and sensing systems.