Scalable Compact Circuit Model for Differential Spiral Transformers in CMOS RFICs

A new compact circuit model for differential spiral transformers in CMOS radio frequency integrated circuits (RFICs) is developed in this paper. The model consists of two coupled “
$hbox2-pi$
” subcircuits for each inductor coil in the transformer. All the values of the circuit elements can be analytically calculated according to the process parameters and the device's geometric dimensions, making the model highly scalable and predictive. The model has very good accuracy as validated by comparison to a 2.5-dimensional full-wave numerical electromagnetic field solver.