Transient analysis of branch-line coupler by using the modified central difference method

In this paper we present an approach to the transient analysis of a branch-line coupler by using the modified central difference (MCD) method with the signal flow graph boundary treatment for the line discontinuities. Multiple reflections on the transmission lines with T-junctions are demonstrated for a step and sinusoidal wave excitations. Additionally, the frequency response is also obtained from the pulse responses of the simulated results. Some examples are presented to illustrate the validity of the proposed method.