A Critical Assessment of the Closed-Loop Bulk Current Injection Immunity Test Performed in Compliance With ISO 11452-4

The closed-loop bulk current injection (BCI) method employed to measure the immunity to electromagnetic interference 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. It is highlighted that, above 100 MHz, the injected bulk current estimated by the calibration procedure described in the standard is significantly different from the actual bulk current injected into the connector of the equipment under test (EUT) during BCI tests. Such a discrepancy gives rise to unreliable BCI immunity test results highlighting susceptibility issues that are not related with the actual susceptibility of the EUT.