▎ 摘　　要

In this article, the intrinsic propagation mechanisms and dispersion properties of the dominant modes supported by different 2-D graphene-based transmission lines (GTLs) at terahertz (THz) are studied in detail. By employing a complete elliptic integral of the first kind, analytical expressions for the wavenumber of plasmons in different GTLs are obtained from the strongly coupled TM mode surface plasmons that propagate on each individual graphene stripline. Besides, per unit length equivalent circuits of different graphene coplanar transmission lines (GCTLs) are introduced. Again, analytical relations between their effective TM mode equivalent circuit lumped elements and graphene surface conductivity are investigated. Moreover, the effects of different GCTLs versus different parameters of the GCTL models for the wavenumber and circuit lumped elements are analyzed. The proposed analytical expressions could reveal the important mechanisms involved in spatially dispersive plasmon propagation connecting with the intrinsic properties of graphene. The features of GCTLs are detailed, showing their great potential for THz applications in future graphene-based nanoelectromagnetic and nanophotonic devices.