The Series Reactance in Coaxial Lines

An experimental investigation has been conducted to determine the effect of a reactance placed in series with the inner conductor of a coaxial line. It was found that capacitive reactances appear in parallel with the inserted series reactance, and in parallel with the resultant impedance of the line at the point where the series reactance is placed. These capacitances can be determined experimentally, and in usual cases are found to be between 10^-14and 10^-12farads. The results of these data have been extended to show the capability of the series reactance as a matching network in coaxial lines, and also its use with hollow cylindrical dipoles. In the course of this investigation it was necessary to determine the capacitance appearing at a step discontinuity in the inner conductor of a coaxial line. The results are in good agreement with values predicted in a previous paper.