Given this integral $$I=\int_\gamma e^{-jk\rho \cos(\alpha-\phi)}d\alpha$$
and given that $k_x=k\cos\alpha $ is such that $k_x \in(-\infty, +\infty)$ and $\phi \in [o, \pi]$
how can I obtain this picture?What's the meaning of the y-axis?
($\alpha$ is complex)
