The implementation of broadband monolithic baluns based on CMOS technology is investigated. The configuration and parameterized layout are analyzed. Then,a wide-band lumped element equivalent circuit model accounting for all necessary physical effects is proposed and model parameters are extracted, with high accuracy in a broadband frequency range ,via combination of physical formula and fitting optimization. Two baluns were implemented with TSMC＇s one-poly eight-metal （1P8M） 0.13μm mixed-signal （MS）/RF CMOS process. The S-parameters of these two baluns were measured using a vector network analyzer. The measured results agree well with the modeled parameters up to millimeter-wave frequencies.
