Investigation on realizing 1 Ω current probe complied with IEC 61967-4 direct coupling method

The practical approach to implement a 1 Ω current probe with verification for measuring the IC conducted emission is proposed. The 1 Ω/150 Ω direct coupling method is reviewed and the considerations on improving the applicable bandwidth of 1 Ω method are discussed. The critical component, 1 Ω resistor which dominates the frequency response, is designed. The realized 1 Ω probe was fully certified with the specification in the IEC 61967-4 standard. The experimental results show the applicable bandwidth of the 1 Ω could cover 1 GHz with accuracy and confidence.