Application of the generalized multipole technique to the analysis of a ladder parallel-plate waveguide for terahertz guided-wave applications

In this paper, a parallel-plate ladder waveguide (PPLWG) is proposed for terahertz waveguiding. A modal analysis of the proposed structure is performed by the use of the generalized multipole technique and is verified using both the mode matching technique and the finite-element method. It is shown that guided modes of this waveguide are TEmy even modes. The dispersion diagram, mode field distribution, and attenuation constant of the dominant mode are also presented. It is shown that by a proper choice of PPLWG dimensions, its mode confinement and dispersion profile can be adapted to typical requirements. Moreover, the field distribution of the dominant mode of a PPLWG can be matched to the TE1 mode of a parallel-plate waveguide which is of practical importance.