HI,
you may try the:
Binomial (maximally flat) Multisection Matching Transformer, there's also a version with equal - ripple response - called Chebyshev MMT.
there is also a book by Pieter Abrie-Design of RF and Microwave Amplifiers and Oscillators, published by Artech House, it has a good portion devoted to broadband maching in general. Also, a book by Brian Minis-Designing MW Circuits by Exact Synthesis, Artech, is a good book to asses your problem
I would suggest doing matching on a smith chart with a constant Q circle. you can control the BW of your matching network by controling its Q. The old DOS base program from motorola has the constant Q circle.