Wideband modeling of RF/analog circuits via hierarchical multi-point model order reduction

This paper proposes a novel wideband modeling technique for high-performance RF passives and linear(ized) analog circuits. The new method is based on a recently proposed s-domain hierarchical modeling and analysis method (Tan, 2003). Theoretically, we show that the s-domain hierarchical reduction is equivalent to implicit moment matching around s = 0, and that the existing hierarchical reduction method by one-point expansion is numerically stable for general tree-structured circuits. Practically, we propose a hierarchical multi-point reduction scheme for high-fidelity, wideband modeling of general passive or active linear circuits. A novel explicit waveform matching algorithm is proposed for searching the dominant poles and residues from different expansion points based on the unique hierarchical reduction framework. Experimental results with large analog circuits, on-chip spiral inductors are presented to validate the proposed method.