Frequency-independent equivalent circuit model for ferromagnetic RF integrated inductors

We have proposed a method for identifying a wide-band equivalent circuit model for ferromagnetic radio frequency (RF) integrated inductors. The equivalent circuit parameters have been extracted from measured S-parameters by using a multiobjective simplex method, which sequentially switches three different cost functions, given by the average of error in Y-parameters, Z-parameters, and S-parameters. With this method, the optimization converged to the global minimum without being trapped at a local minimum. Calculated Y-parameters, Z-parameters, and S-parameters were in good agreement with the measured results in the range of dc to 20 GHz.