Wideband Balun

hi
I would like to use wideband balun in two arm archimedean spiral antenna design in CST.
Any one have wideband balun papers, or wideband balun theory or R.P.Hecken optimum impedance matching, or Klopfenstein impedance matching papers or pdf books.

Plz if you have , can you send it to my id kallyany@gmail.com

thank you

A few things, you can find some very useful information at the following document:

http://www.ctsystemes.com/zeland/publi/pg40.pdf

also search for guanella transformer or current balun.

if you want ultimate bandwidth search for Minerva Duncan paper on wideband balun.

J. W. Duncan and V. P. Minerva,. "100:1 Bandwidth Balun Transformer".