multimatch ampsa
If you cannot get a comment by a user of this software, my suggestion will probably be better than nothing. I have looked at this program. It seems to do single pass type designs. That is, it does not have a real simulator. Every impedance matching program I have tried does not take the transition problems between different lines into account. (The junction produces higher order modes that act like a shunt reactance.) You always have to put the design in a simulator (that models these effects) and do an optimization.