Transfer Impedance Measurements – a Practical Approach

Transfer impedance is a very central parameter in
determining the quality of a cable shield. It has been
under investigation through several decades. Many
different test setups are available as [1] summarizes and
contrasts, but all methods require either a considerable
test setup or calibration effort.
This poster presents a method to practically determine
the transfer impedance of shielded cables using a vector
network analyzer. It provides a theoretical model and the
equivalent circuit. The practical test setup can be rebuild
with little effort while still providing reliable results in the
low frequency range. A bulk current injection (BCI) into
the outer conductor of a shielded cable of an RG-58
coaxial cable requires only two test runs and little post
processing.