An alternative method for measuring the transfer impedance of coaxial and data cables

Abstract

Transfer impedance (Zt) is a key parameter for evaluating coaxial and data cable shielding effectiveness (SE). Standard measurement methods such as injection and triaxial methods are widely used. However, this paper focuses on an experimental approach based on the principles described in two scientific studies [1], [2], which have not been described in detail outside the sources cited. The proposed method uses direct signal injection through a precisely dimensioned transmission channel and analyses the phase relationship of two S-parameters-the reflection coefficient and forward gain. This approach allows for efficient and reliable Zt determination without modifying the tested cables. The method was extended to include the possibility of measuring data cables in this study, thus expanding its application area. The experiment included measurements of different types and lengths of coaxial cables, while a selected type was tested for data cables. The results confirm that the presented method provides consistent and reproducible Zt values with the potential for further development for a broader range of cable structures.