A broadband and scalable T-model for on-chip inductors

An extended T-model has been developed to simulate broadband characteristics of spiral inductors. With parallel and shunt to ground resonators, the extended T-model can characterize an inductor for arbitrary bandwidth. The extended T-model had unveiled its accuracy to wide bandwidth but the feasibility of scalable T-model has not been proposed. In this paper, the T-model and a curve fitting method are used to construct a broadband model for on-chip spiral inductors. A series of spiral inductors were fabricated and analyzed to construct a scalable model by the proposed method. To verify the accuracy of scalable T-model, an interpolated inductor was also fabricated and measured. The measured S parameters agree quite satisfactorily with that of scalable T-model up to the second self-resonant frequency of the inductor.