Stability, Causality, and Passivity of Canonical Equivalent Circuits for Improper Rational Transfer Functions-Part II: With Complex-Conjugate Poles and Residues

• Published in: IEEE access 2023, Vol.11, p.108995-109009
• Main Authors: Choupanzadeh, Rasul, Zadehgol, Ata
• Format: Article
• Language: English
• Subjects: Algorithms; Asymptotic stability; Causality; Circuit stability; Conjugates; equivalent circuit; Equivalent circuits; Frequency-domain analysis; improper rational transfer function; Millimeter waves; Optoelectronics; Parameters; passivity; Poles; Residues; Shunts (electrical); single-input single-output (SISO); SISO (control systems); SISO communication; SPICE; stability; Stability analysis; Stability criteria; Time-domain analysis; Topology; Transfer functions
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2023.3321631

This paper presents a comprehensive analysis of stability/causality/passivity (SCP) for improper rational transfer functions (TFs) with complex-conjugate pair of poles/residues, as an extension of real poles/residues case in our previous work. We derive and validate the frequency-domain constraints of SCP for improper rational TFs with complex-conjugate pair of poles/residues, equivalent to an R-L-R-C circuit branch in parallel with \text{R}_{\textit {shunt}} and \text{C}_{\textit {shunt}} elements. We present a novel algorithm for SCP assessment of single-input single-output (SISO) systems at the cellular circuit level, including detailed tables to establish the relationship between the TF parameters (pole, residue, zero), the equivalent circuit parameters (R, L, C), and the SCP conditions, for an improper system of R-L-R- \text{C}\parallel \text{R}_{\textit {shunt}} \parallel \text{C}_{\textit {shunt}} circuit branches. The aforementioned circuit-block structure serves as an important canonical topology for macromodeling of electrical systems across numerous applications. The presented methodology may be used for synthesis of guaranteed-stable SPICE equivalent circuits of electrical systems represented by network parameters (e.g., S/Y/Z-parameters), including power systems operating at tens of Hertz (Hz), high-speed \mu wave/mm-wave electronics operating at hundreds of MHz/GHz, and ultra high-bandwidth opto-electronic and optical systems operating at hundreds of THz.