Critical equipment input impedance measurement for IEMI calculations

In this work, we discuss the need for measuring the input impedance of critical equipment for correctly modelling the IEMI coupling to critical infrastructures. A measurement methodology that employs a traditional VNA and a test fixture for retrieving the differential input impedance of an N-port network is presented. The advantage of the proposed method is that it permits the measurement of the differential impedance among all the input ports of the same equipment under test by using a conventional two-port VNA.