wideband impedance mathching

does anyone have information, book or any relevant material on how wide band mathcing is done. in current literature we only find matching at single frequencies and currently all systems are working on wideband....so how is matching achieved at a wide range of frequencies....
could some one provide links or books or any information you might have...

Hi,
The wideband matching method depends on the requirements of your device. Tipically it is achieved using a taper (Klopenstein or Exponential), which adapts the input and output impedance over a wide range of frequencies, depending mainly on the dimensions of the taper.
Hope it would help.-

The only practical way of wide-band matching is use of resistors or attenuators. Bode-fone theorem states that it is practically impossible to match over wide bandwidth.

You can also use screws for impedance matching over a wideband.

You can read more about Bode-Fone thm here: Ultra Low Power Bioelectronics ... - Google Books
and Fano's original paper: http://www.mrc.uidaho.edu/~jyoung/EE539/fano.pdf

The Bode-Fano criterion shows that you cannot reach a perfect matching over a wide range of frequencies, but a wideband impedance mathching can be obtained over a wide range if you define a maximum reflection coefficient for your application.