% Author: Prof. Dr. Matthias Jung, DL9MJ
% Year: 2023
\begin{circuitikz}
    \draw[DARCred,thick] (0,2)
        sin ++(4, 1)
        cos ++(4,-1);
    \draw[DARCred] (0.25,2.5) node[](){$I$};

    \draw[very thick] (0,2) coordinate(start)
        to [short] ++( 3.9,   0)
        to [short] ++(   0,-0.8);
    \draw[very thick] (8,2) coordinate(end)
        to [short] ++(-3.9,   0)
        to [short] ++(   0,-0.8);

    \draw[DARCblue,thick] (0,-2) 
        cos ++(4, 1)
        sin ++(4, 1);
    \draw[DARCblue] (0.25,-2.5) node[](){$U$};

    \draw[very thick] (0,-1) coordinate(start)
        to [short] ++( 3.9,   0)
        to [short] ++(   0,-0.8);
    \draw[very thick] (8,-1) coordinate(end)
        to [short] ++(-3.9,   0)
        to [short] ++(   0,-0.8);

    \draw[DARCorange, fill=orange, thick] (4,3) to [short, *-*] (4,-1);
    \draw[DARCorange, fill=orange, thick] (0,2) to [short, *-*] (0,-2);
    \draw[DARCorange, fill=orange, thick] (8,2) to [short, *-*] (8,-0);

    \DARCmeasure{start}{end}{0,-2.0}{0}{$\frac{\lambda}{2}$}
\end{circuitikz}