Practical considerations for passive reduction of RLC circuits

Krylov space methods initiated a new era for RLC circuit model order reduction. Although theoretically well-founded, these algorithms can fail to produce useful results for some types of circuits. In particular controlling accuracy and ensuring passivity are required to fully utilize these algorithms in practice. In this paper we propose a methodology for passive reduction of RLC circuits based on extensions of PRIMA, that is both broad and practical. This work is made possible by uncovering the algebraic connections between this passive model order reduction algorithm and other Krylov space methods. In addition, a convergence criteria based on an error measure for PRIMA is presented as a first step towards intelligent order selection schemes. With these extensions and error criterion examples demonstrate that accurate approximations are possible well into the RF frequency range even with expansions about s=0.