Modeling methodology of integrated five-port balun using two-port RF measurement

A comprehensive investigation of RF characteristics and RF modeling methodology of integrated transformer/balun fabricated by 0.18um, mixed signal process are presented. We proposed an improved lumped-element equivalent circuit and a three-step method to characterize and model the five-port balun by using a standard two-port RF measurement. The frequency dependence of inductance and resistance resulted from skin, proximity effects and eddy current loss is considered in the lumped-element model. Both inverting and non-inverting configuration were examined to enhance the model accuracy. The fitting results perform good agreement with measurements over the frequency range of 0.1 - 6GHz.