The routine plots normalized impedance in a Smith chart, i.e. by conformal mapping or Moebius mapping.
The routine handles reflection coefficient values outside the unit Circle, i.e. active circuits. The routine is based on the polar.m routine from MATLAB and is free from the legend problems pertaining to other MATLAB routines for the same purpose.
Known shortcomings of the present version are that the radii of the Grid circles are hardwired, and that the grid has no units. Feel free to add this functionality if you wish.