Southwest Microwave, Inc., conducted this study to explain and explore the benefits of using time-domain reflectometry (TDR) to design transitions, like the ones between end launch connectors and printed circuit boards. If there are discontinuities in the electrical performance, the TDR function should help designers in determining the nature and location of them. TDR is a technique used for applications beyond designing transmission lines, but for the purposes of this study, the only TDR measurements that are discussed are those that are directly pertaining to transition analysis.

This white paper goes over the basic principles of TDR measurements (as they relate to discontinuity analysis). Examples on how to use TDR analysis to optimize boards and explanations as to the limitations of time-domain measurements are also given. TDR measurements can be an invaluable tool for optimally designing transition lines—when they’re used properly. If the results are misunderstood or misinterpreted, it’s easy to make mistakes which are damaging to effective transmission line design. Transmission line designers are encouraged to work on using effective TDR analysis to optimize their lines, especially when a microwave coaxial connector transition is included.