The Interpretation and Use of S-Parameters in Lossy Lines

Abstract

Although a fundamental parameter of transmission lines, the charac. teristic impedance is difficult to measure accurately. We suggest a method by which it may be easily determined from a measurement of the propagation constant. The method is based on a rigorous analysis from first principles using explicit and realistic approximations which include the effects of imperfect conductors. Results of numerical studies of lossy coaxial lines and of experiments with coplanar waveguides indicate that high accuracy is possible.