Passive Reduced-Order Models for Interconnect Simulation and Their Computation via Krylov-Subspace Algorithms

This paper studies a general projection technique based on block Krylov subspaces for the computation of reduced-order models of multi-port RLC circuits. We show that the resulting reduced-order models are always passive, yet they still match at least half as many moments as the corresponding reduced-order models based on matrix-Pade approximation. Moreover, for the special cases of RC, RL and LC circuits, the reduced-order models obtained by projection and by matrix-Pade approximation are identical. For general RLC circuits, we show how the projection technique can easily be incorporated into the SyMPVL algorithm to obtain passive reduced-order models, in addition to the high-accuracy matrix-Pade approximation that characterizes SyMPVL, at essentially no extra computational costs. Connections between SyMPVL and the recently proposed reduced-order modeling algorithm PRIMA are also discussed. Numerical results for interconnect simulation problems are reported.