TABLE OF CONTENTS In this chapter, we presented the basic concepts for the model order reduction of interconnect circuits based on Krylov subspaces. We started with the concepts of moments, Elmore delays, and the Pade approximation for moment matching. We introduced the classic moment matching techniques like AWE, which suffer from the numerical issues. Then we presented the projection-based reduction framework and concepts of Krylov subspaces, which lead to more numerical stable model order reduction methods. Finally, we showed how model order reductions can be applied to RLC circuits and produce passive models via some numerical stable processes like Arnoldi and Lanczos methods for both SISO and MIMO systems.
