▎ 摘　　要

In this paper, the concept, analysis, and synthesis of a novel plasmonic leaky wave antenna (LWA) based on the modulated radius of a cylindrical graphene waveguide (CGW) at the terahertz band are presented. Devices based on the planar graphene waveguide (PGW) suffer from high attenuations, which significantly limit the radiation efficiency and beam width of LWAs. It is shown here that the LWA based on CGW compared to PGW can decrease the beam width from 55 & DEG; to 12?degrees and increase the radiation efficiency from 20% to 50%. A sinusoidally modulated graphene surface is employed to excite the leaky wave antenna. A sinusoidally modulated reactance surface is realized by the modulation of the radius of the cylindrical waveguide. In comparison to other structures, the proposed antenna can be implemented by applying a single voltage to graphene sheets. As a result, the antenna beam direction can be readily changed by varying the applied voltage. (C) 2021 Author(s).