Discontinuity effects for a cascaded transmission-line system consisting of two line sections of different height

The transmission characteristics of finite-length transmission lines (TLs) having two sections of different height are studied by using a circuit concept; the line system consists of two line sections and three vertical risers. There exist electromagnetic fields due to currents in the risers and the line sections of the line system. Therefore the vertical-riser effects on transmission characteristics should be considered in addition to the ordinary characteristics. The propagation mode along the TLs involves the transverse electromagnetic (TEM) mode and others. The effects of the disturbing fields are added to telegrapher´s equation as forcing terms. The modified equation is applied to estimate the riser effects on the line section. From solutions of the equation, a network matrix in terms of terminal voltages and currents is obtained. In order to verify the theory, a comparison between the results calculated by the compensated and the ignored risers theories, respectively, and those measured for an input voltage reflection and the transmission coefficients are made for some models