The conceptual design of microwave test circuits for evaluating competing formulations of reflection coefficient

The author discusses some techniques by which to evaluate, experimentally, competing formulations of the generalized reflection coefficient R(x), where x is the position, for inhomogeneous media (IM) and nonuniform waveguiding structures (NOWSs). The two under consideration are called here the Walker-Wax formulation, denoted by R/sub w/(x), which was first published in 1946, and a newer power-based formulation, denoted by R/sub p/(x). That conceptual flaws could exist within R/sub w/(x) after more than four decades of heavy use by the electromagnetics and acoustics communities may seem highly unlikely. But the special measurement techniques discussed, required to display some of those flaws, are only part of the explanation. Methods are outlined for measuring forward and backward traveling power components within IM and NOWS in such a manner that neither formulation needs to be invoked to interpret measured data.