Non-Uniqueness of T-Charts for Solving Ccitl Problems with Passive Characteristic Impedances
Conjugately characteristic-impedance transmission lines (CCITLs) implemented by lossless periodic transmission-line structures have found various applications in microwave technology, and the T-chart was developed to perform the analysis and design of CCITLs effectively. Originally, the normalization factor used in defining normalized impedances of the T-chart is the geometric mean of characteristic impedances of CCITLs, which is not only one possible choice. By using other normalization factors based on characteristic impedances, different graphical representations can be obtained; i.e., T-charts for CCITLs with passive characteristic impedances are not unique, and it depends on the associated normalization factor. In this study, three more possible normalization factors related to characteristic impedances of CCITLs are investigated. It is found that all T-charts for each normalization factor are strongly dependent on the argument of characteristic impedances of CCITLs in a complicated fashion. The original T-chart based on the geometric mean of characteristic impedances is found to be the most convenient graphical representation for solving CCITL problems.