Measuring the Complex Surface Transfer Impedance: A Critical Review of Existing Methods

For analysing the coupling to extended cable systems or investigating the coupling by transient signals to cables, it is necessary to know the surface transfer impedance ZT as an intrinsic property of the cable. Furthermore, it is important to have the full complex ZT. Several existing measurement test fixtures are examined as to whether they deliver ZT in complex form and as an intrinsic property of the cable. Error sources are discussed for the triaxial, terminated triaxial / quadraxial and MIL-Std. test fixtures. A modified version of the widely accepted standard IEC 96-1A procedure is shown which simplifies the measurement effort.