By Ian Darney
In any analysis of EMI, the most critical parameter is the Transfer Admittance – the ratio of the current delivered to the victim loop to the voltage applied to the culprit loop.
In the case of the configuration under review, the culprit loop is that carrying the differential-mode signal and the victim loop is that between the cable and the virtual conductor simulating the environment. Here, the Transfer Admittance defines the emission characteristic.
If the voltage source was in the antenna-mode loop, then the Transfer Admittance would be the ratio of the current induced in the differential-mode loop to the amplitude of that voltage source. This is a measure of the susceptibility of the configuration.