A critical assessment of the closed-loop Bulk Current Injection immunity test performed in compliance with ISO 11452-4

In this paper, the closed-loop Bulk Current Injection (BCI) method, that is employed to measure the immunity to Electromagnetic Interference (EMI) of an electronic equipment in compliance with the ISO 11452-4 standard, is critically assessed on the basis of an experimental characterization of its test setup. In particular, it is highlighted that the injected bulk current estimated by the calibration procedure described in the standard is significantly different from the actual bulk current injected into the EUT connector during BCI tests above 100MHz. Such a discrepancy gives rise to unreliable BCI immunity test results highlighting susceptibility issues that are not related with the actual susceptibility of the equipment under test. The characterization technique considered in this paper could be adopted to define an alternative procedure to estimate the EUT-level injected bulk current in BCI tests.