Description of electromagnetic effects in the transmission line theory via concentrated and distributed linear elements

The transmission line theory (TLT) is an excellent tool to calculate the wave propagation along of conducting metallic materials in an isolating dielectric environment if some prerequisites are fulfilled. They allow the splitting of the propagation process in two independent problems. A one-dimensional wave propagation in the direction of the conductor axes and a two-dimensional quasi static problem in all planes perpendicular to the direction of propagation. The achieved results are good if the system in which the wave propagates is homogeneous and small in comparison with the minimum wavelength but in realistic line arrangements existing irregularities cause effects which cannot be handled by use of the traditional TLT because they cause three-dimensional field effects. We show that it is possible to take the three-dimensional effects into consideration by definition of an additive and homogeneous ohmic resistance per unit length which represents the radiation losses and two-ports which are positioned at the locations of bends along the line.