Experimental Study of Radiated Immunity Impact Analysis due to Conventional and Broadband Signal Sources

The radiated immunity standard IEC 61000-4-41, which utilizes orthogonal frequency division multiplexing (OFDM) signal sources to address the drawbacks of existing immunity test signal sources such as IEC 61000-4-3, 61000-4-39 and ISO 11452-1, is currently being developed. This study was conducted to compare and analyze the impact of existing test signal sources and OFDM signal sources on the EUT. Various signals, including continuous wave(CW), amplitude modulation(AM), pulse modulation(PM), and an OFDM signal within the 20 MHz bandwidth, were used for RI tests at a 1 meter distance from the antenna to the EUT. Comparing the impact of each signal based on the immunity level as a reference parameter, it is revealed that the OFDM signal had the lowest immunity level across most of the frequency ranges. During the immunity test, CE in the low-frequency range (9 kHz to 30 MHz, CISPR standard) were also measured using a LISN. When malfunctions occurred in the EUT, it was observed that the CE spectrum remained almost unchanged up to 20 MHz, but the CE spectrum changed quite a lot with malfunctions, especially in the frequency range from 20 MHz to 30 MHz.