Modeling of Monolithic Spiral Inductors with Patterned Ground Shield for Si-Based RF IC's

An improved single-π equivalent circuit model with patterned ground shield is presented in this paper. The monolithic spiral inductor uses metal 1 and metal 2 as a ground shield which forms a good isolation between substrate and passive device at the high frequency. To accurate model for spiral inductor under the high frequency, a parallel L-R network is adopted to represent the high-order effects. A C-L-R network to model the ground loop in the lower metal strips. Within the wide bandwidth, the modeling and parameter extraction methods have been validated by the excellent agreement between the circuit model and EM-simulation up to 40GHz.