A model reduction method utilizing the rational Arnoldi method with
adaptive orders (RAMAO) is applied to high-speed VLSI interconnect
models. The method is based on an extension of the classical multi-point
Pade approximation, using the rational Arnoldi iteration approach. Given
a set of predetermined expansion points, an exact expression for the
error between the output moment of the original system and that of the
reduced-order system, related to each expansion point, is derived first.
In each iteration of the proposed RAMAO algorithm, the expansion
frequency corresponding to the maximum output moment error will be
chosen. Hence, the corresponding reduced-order model yields the greatest
improvement in output moments among all reduced-order models of the same
order.