create a Media from numerical values stored in a csv file.
the csv file format must be written by the function write_csv() which produces the following format
f[$unit], Re(Z0), Im(Z0), Re(gamma), Im(gamma), Re(port Z0), Im(port Z0) 1, 1, 1, 1, 1, 1, 1 2, 1, 1, 1, 1, 1, 1 .....