Modeling of planar transformer with a unified CPW model

A planar transformer circuit derived from a unified CPW mode is presented. The elements of the model are calculated directly from the equations for CPWs and the transformer geometries. The substrate eddy current losses and coupling with the transformer lines are modeled by RL network structures and mutual inductances. One turn planar transformers have been designed and fabricated on various resistivity substrates. A good agreement is obtained between the measurement and the equivalent circuit. This work demonstrates the application of the unified model for transformers.