A novel iterative method for approximating frequency response with equivalent pole/residues

Frequency domain modeling of interconnects has become the de facto standard for characterization in high-speed signal and power delivery systems. But time domain system level performance analysis calls for pole/residue representation followed by circuit level synthesis from the frequency domain sampled data model of interconnects. In this paper, a new iterative method that produces a set of equivalent poles and residues from discrete sampled frequency response data is proposed. Each iteration picks a few consecutive points from the given sampled response, identifies a local transfer function that matches their response and reduces error by subtracting the local transfer function. Two test cases, strip-line and package, are demonstrated. And results show that the proposed method has potential in fitting system frequency responses and has wide applications in signal and power integrity modeling and simulation of interconnect networks.