Termination impedance for AC mains cable leaving from EUT area in radiated emission measurement

In regard to the influence of AC mains cable termination on radiated emission, we compared and analyzed the simulation results in single-wire and 3-wire line configuration by round-robin testing with a comb generator and tower PC. The analysis result demonstrates that the deviation with 25-ohm and 150-ohm termination and the deviation with a comb generator and a tower PC using a very high frequency line impedance stabilization network (VHF-LISN) and coupling/decoupling network (CDNE) are nearly equal. Thus, single-wire simulation reflects the result using a comb generator in RRT, and 3-wire simulation reflects the result using a tower PC. Based on these findings, we compared deviations of average values of radiated field strength of the comb generator and tower PC by VHF-LISN and CDNE, with based on “without termination device.” We thereby conclude that the terminating each line with 50 Ω by VHF-LISN is the proper way.