Pole-Zero Identification: Unveiling the Critical Dynamics of Microwave Circuits Beyond Stability Analysis

TL;DR

This paper reviews pole-zero identification methods for analyzing nonlinear microwave circuits, emphasizing their role in stability analysis and model reduction, with illustrative examples and a comprehensive overview of recent approaches.

Contribution

It provides a comprehensive review of pole-zero identification techniques applied to nonlinear microwave circuit analysis, highlighting recent developments and practical applications.

Findings

Pole-zero identification aids in nonlinear circuit stability analysis.

Recent approaches improve model accuracy and computational efficiency.

Illustrative examples demonstrate practical applications in microwave engineering.

Abstract

Pole-zero identification refers to the obtaining of the poles and zeros of a linear (or linearized) system described by its frequency response. This is usually done using optimization techniques (such as least squares, maximum likelihood estimation, or vector fitting) that fit a given frequency response of the linear system to a transfer function defined as the ratio of two polynomials. This kind of linear system identification in the frequency domain has numerous applications in a wide variety of engineering fields (such as mechanical systems, power systems and Electromagnetic Compatibility). In the microwave domain, rational approximation is increasingly used to obtain black-box models of complex passive structures for model order reduction and efficient transient simulation. In this paper we will focus on a different application of pole-zero identification. We will review the different ways in which pole-zero identification can be applied to nonlinear circuit design (for power amplifier stability analysis and beyond). We will give a comprehensive view on recent approaches through illustrative application examples. Other uses of rational approximation techniques are beyond the scope of this paper.