Influence of Injection Point Selection on Military Low Frequency Immunity Test Results

The MIL-STD-461F CS101 test is one of the essential low-frequency conducted immunity tests for military and aerospace equipment between 30 Hz and 150 kHz, however it includes some challenges and pitfalls in application. The major pitfall is the necessity for the measurement of injected CS101 ripples across the EUT and also across the power source side under the presence of the power frequency of the EUT, whose solutions have been thoroughly studied and introduced in our earlier papers. The other critical pitfall is that the influence of the injection point and the decoupling capacitor position may reach significant levels especially beyond 30 kHz. Therefore, in this research, we extensively study and demonstrate the influence of the positions of the injection point and the $10 \ \mu\mathrm{F}$ decoupling capacitor on test results especially as from 30 kHz and ultimately propose solutions to this issue.