A bulk current injection test conforming to statistical properties of radiation-induced effects

In this paper, a bulk current injection (BCI) immunity test is designed that conforms to the effects induced in the equipment under test (EUT) by a radiated electromagnetic disturbance (EMD). This is done by adopting a statistical description of the EMD and by comparing currents induced by BCI and distributed field-coupling (i.e., radiation) in the input pins of the EUT. Closed-form results are obtained that enforce equivalence of the aforementioned test procedures in terms of specific statistical estimates (e.g., expected value and dispersion) as well as for worst-case radiation-induced effects. A distributed-parameter circuit model of the system under test is adopted, composed by the EUT, auxiliary equipment (AE), and a wiring harness. In the analysis, the EMD is described via plane waves with random parameters and a uniform multiconductor transmission line model is used for the wiring harness. The EUT and AE are represented via lumped impedance matrices. Injection-probe feeding-conditions assuring equivalence are derived analytically, and involve a frequency piecewise-linear profile of the RF voltage source. The proposed BCI immunity test overcomes practical-design difficulties of previous formulations.