An identification technique for macromodeling of long interconnects

We consider the problem of the identification of describing functions for the reduced time domain modeling of interconnects. In particular we identify the rational approximation of regular parts, once delays are exactly extracted, with a combination of vector fitting algorithm with a post-processing procedure based on a non linear least square refinement step. This improves the accuracy of the approximation obtained, and leads directly to rank-1 residue matrices. The technique is applied to a couple of test cases and a comparative evaluation of performances is carried out.