Years ago, Fano published an important paper regarding the theoretical limitations on the broadband matching of reactive loads. His paper, a true classic, is, unfortunately, unfamiliar to many young engineers.

What Fano did was to prove that, given a series or parallel RC or RL load, was that there exists a finite limit on the minimum attainable VSWR across a given band of frequencies, even when using a match network with an infinite number of elements in it.

This is profound, and a remarkable achievement. His work today is referred to as "The Fano Limit." Using the work of Fano, you can determine, up front, the best that can be done in any reactive match situation. Why spin your wheels endlessly trying to do better than the theoretical limit?

Keep in mind that, in practice, there is no way you can actually reach Fano's limit, as it is based on an IDEAL reactive load, but you can approach it. If you would like to see a reference to an article entitled "Calculator program finds Fano bandwidth," written by Microwave Software President, James J. Lev, see Appendix E.