A Simple Measurement Method for Frequency-Dependent Impedance and Parasitic Parameters of Common-Mode Chokes

One more useful measurement and identification method for common-mode chokes is proposed to analysis frequency-dependent impedance and parasitic parameters information within the balanced frequency range. Equivalent circuit for common-mode chokes is established according to the reciprocal and symmetric physical structure, and S-parameters measured with vector network analyzer have been performed to determine the balanced frequency range. Measurement and identification for frequency-dependent impedance and parasitic parameters has been detailedly discussed, and the corresponding results are obtained through theoretical analysis and calculation. As per the frequency-dependent impedance and parasitic parameters, common-mode and differential-mode signal transmission characteristic within the balanced frequency range can be easlily analyzed, and application performance of common-mode chokes will be improved by optimizing the winding structure or choosing the suitable magnetic material.