Jerry Sevick, W2FMI, is the author of the amateur radio classic, Understanding, Building, and Using Baluns and Ununs and the more engineering-oriented, Transmission Line Transformers. He’s done more to take the black magic out of baluns than anyone in ham radio, and I was pleased to hear him speak at this year’s Dayton.
He recently published a series of articles on the topic in the trade magazine High Frequency Electronics. They’re all online and all worth reading:
- A Simplified Analysis of the Broadband Transmission Line Transformer
- Design of Broadband Ununs With Impedance Ratios Less than 1:4
- Magnetic Materials for Broadband Transmission Line Transformers
There’s lot of other good stuff on the High Frequency Electronics website, too. The editor, Gary Breed, K9AY, is a well-known amateur radio operator, and there’s lots of good stuff there for guys like us, even though it’s really aimed at RF engineers.