Most high-frequency and miniaturized power inductors are metal molding-type inductors. The magnetic metal powder surfaces are usually treated with an oxide layer to reduce eddy current losses at high frequencies, enhancing the usable frequency range and reducing losses and temperature rising. However, users typically cannot determine the particle size of the magnetic material and the integrity of the oxide layer after molding and sintering through visual inspection alone. Traditional testing based on the nominal frequency of the inductor measures the inductance value and Q value. Since the impedance state of high-frequency miniaturized inductors is low, the Q value is often influenced by the contact resistance of the probe.
