An Optimized Modeling Method for Transformer Design

Abstract

This paper presents an optimized modeling method for transformer design in the narrow-band application. In order to improve the accuracy of analysis, the parasitic capacitors are contained in the equivalent circuit model. According to the model, the parameters of transformer with maximum efficiency can be obtained. The transformer is used in the output impedance matching of power amplifier with a turn ratio of 2:3 in 40-nm CMOS process. Equality factor Q of primary and secondary toil of transformers are 9.28 and 14.19 respectively, while the coupling coefficient is 0.83. This method is demonstrated to be efficient according to the post simulation on a power amplifier with 25dBm saturated power and 19% PAE when the input power is OdBm in 2.4GHz under 3.3V voltage supply.