smith-chart plotting

[Tobias Drößler]

hi,

i use  scilab to evaluate and display solutions of electromagnetic 
simulations.
in high frequency - engineering the smithchart is used to visualize 
complex values in one diagram.

it looks like this :  http://www.ece.msstate.edu/~donohoe/smithchart.gif

I am searching for an function/toolbox  that plots data  in this format.
Is there something like that available ??

if not, may i will build up something  - which way is suggest to do that 
?  a  scilab function which draws at first the diagram itself and than 
plots data in it, or are there better possibilities?

thanks for your help.

regards  Tobias