\begin{equation*} \boxed{\boldsymbol{I(x,t)=\frac{1}{{{{Z}_{c}}}}\left( {{{V}_{d}}{{e}^{{-\alpha x}}}{{e}^{{j(\omega t-\beta x+{{{{\varphi }}}_{d}})}}}-{{V}_{r}}{{e}^{{\alpha x}}}{{e}^{{j(\omega t+\beta x+{{{{\varphi }}}_{r}})}}}} \right)}} \end{equation*}