Two current probes, based on the current injection method, are designed with appropriated high frequency magnetic material. These probes are used to measure the common-mode impedance of power converters in real-operating conditions. The characterization of this impedance is of importance for the EMI filter design. In this paper, a simple formulation of the probe's transfer impedance using S-parameters is proposed. The proposed probe allows improving the accuracy of the impedance measurement in a wide frequency band up to 100 MHz. Different measurements of common-mode configurations are detailed and discussed. © 2013 IEEE.