Modeling of Planar Transformers Based on PEEC Method

Accurate parasitic extraction of the planar transformers includes the modeling of magnetic components and the complicated printed circuit boards (PCB) structures. In this paper, a volume-based partial element equivalent circuit (PEEC) method is used to accurately characterize the resistance, inductance, and the loss caused by the magnetic components. The tetrahedral grids are used to provides a proper approximation for the via, slotted planes and the package structure, which also allows the accurate modeling of the copper losses at low frequencies. Moreover, the excitation can be flexible assigned over the structures due to the interpretation of the model circuitization. Finally, the algorithm is applied to extract parameters of a typical planar transformer and compared for accuracy with commercial software to demonstrate the feasibility of the method. The relative error within the relevant frequency range, when compared to Maxwell, is less than 10%.