An Analytical Broadband Model for Millimeter-Wave Transformers in Silicon Technologies

A lumped element model to represent the behavior of millimeter-wave (mm-wave) integrated transformers is presented. Details on the topology allowing efficient mm-wave operation are given. The model presents a 2- π architecture and contains the equations to evaluate its components values. These equations depend on both technological and geometric characteristics of the transformer. The model is validated through experimental data of a set of 65-nm CMOS and 130-nm BiCMOS transformers. A very close agreement is shown for both S-parameter and inductance values up to 110 GHz.