5. Other formulations of line theory

The theory of lines can be approached in other ways than those discussed so far in this article, which we propose to outline briefly in this section. First, the input impedance formalism will be examined, the aim of which is to deduce certain physical properties of lines by means of a compact formula. This relationship allows us to reproduce the evolution of the impedance seen at the input of a line connected at the output to any impedance Z _L . In the second part, a line will be assimilated to an electrical quadripole in order to naturally integrate the contribution of propagation phenomena. The coefficients of the chain matrix will be calculated, and some examples of this approach will be illustrated. The third and most consequential part deals with the resolution of lines using symbolic calculus. The advantage of symbolic calculation is that...