A novel broadband technique to effectively launch plasmons along a single
graphene layer at terahertz (THz) frequencies is proposed. To this end, the
coupling of the electromagnetic wave from a readily available plasmonic
waveguide established by a periodically corrugated metallic surface to the
graphene sheet is proposed. As will be shown, this technique can significantly
surmount the need for efficient excitation of plasmons in graphene. For this
purpose, an analytical technique based on transmission line theory is employed
to calculate the scattering parameters of the connection of the plasmonic
waveguides. In this manner, the gating effects of the graphene waveguide on the
input reflection and transmission of the junction are also investigated. For
comparison, a full wave numerical simulator is employed