\begin{tikzpicture}
\pgfplotsset{every x tick label/.append style={font=\tiny, yshift=0.5ex}}
\pgfplotsset{every y tick label/.append style={font=\tiny, xshift=0.5ex}}
\begin{axis}[
    xmin=-10,
    xmax=10,
    ymin=-2,
    ymax=2,
		xtick = {0},
		ytick = {0},
    axis equal,
    axis lines=middle,
    disabledatascaling]



\node[font=\tiny] at (axis cs:-5,0) [anchor=north west] {-R};
\node[font=\tiny] at (axis cs:5,0) [anchor=north east] {R};
\node[font=\tiny] at (axis cs:5,-5) [anchor=north east] {R - ib};
\node[font=\tiny] at (axis cs:-5,-5) [anchor=north west] {-R - ib};

\node[font=\tiny] at (axis cs:5,6) [anchor=north west] {$\mathbb{C}$};

\begin{scope}[thick,decoration={
    markings,
    mark=at position 0.5 with {\arrow{>}}}
    ] 

		\draw[-][black][opacity=0.9, postaction={decorate}] (axis cs:-5.0, 0) -- (axis cs:-5, -5);
		\draw[-][black][opacity=0.9, postaction={decorate}]  (axis cs:5, -5) -- (axis cs:5.0, 0);
		
		\draw[-][black][opacity=0.9, postaction={decorate}] (axis cs:5, 0) --  (axis cs:-5.0, 0);
		\draw[-][black][opacity=0.9, postaction={decorate}] (axis cs:-5.0, -5.0) -- (axis cs:5,-5);
\end{scope}


\end{axis}
\end{tikzpicture}