Assessing the performance of a current probe based method for determining surface transfer impedance

Surface transfer impedance is a useful measure of the shielding performance of a coaxial cable for predicted or known EMC environments. However, the standard method for determining this, the triaxial method, does not lend itself readily to bench-type tests. As a result, a number of alternative methods have been proposed and illustrated, most requiring the cable under test to be specially prepared. This paper describes a method for cable testing which does not require cables to be specially prepared and which also avoids the limitations of very short electrical lengths, required by some of the other methods. Results are presented illustrating the accuracy of the method, which is shown to be comparable to other bench methods but with considerably improved testing time