Direct extraction method of equivalent circuit parameters for stacked transformer

A parameter-extraction approach for the stacked on-chip transformer, which combines the analytical approach and the empirical optimization procedure, was developed. The model parameters determined from the analytical expressions were considered as an initial guess of a subsequent optimization procedure leading to the final model parameters. Good agreement was obtained between simulated and measured results for a stacked transformer on silicon substrate in the frequency range 100 MHz~60 GHz.