Limitations of First-Order Surface Impedance Boundary Condition and its Effect on 2D Simulations for PCB Transmission Lines


Signal integrity (SI) issue is a critical concern as the data rate continues to increase and SI analysis is heavily dependent on simulations. Inaccurate simulation data may result in inadequate design decisions influencing high-speed digital design and optimization. The surface impedance boundary condition (SIBC) concept is generally utilized in commercial electromagnetic (EM) solvers, which is considered to be an efficient technique as the interior region of the conductor of interest does not need to be included in the numerical procedure. The first-order SIBC has been incorporated into many EM simulation tools widely used in industries. In this paper, the limitations of the first-order SIBC in 2D simulations for PCB transmission lines are analyzed and demonstarted for the first time. Different PCB transmission lines with various cross-sectional geometries are simulated in a commercial 2D EM solver with and without the implementation of the first-order SIBC to reveal the effect on the simulated transmission line behaviors. It is found that the accuracy of the simulations with the first-order SIBC decreases as the edge of the signal conductor in the cross-section becomes narrower. The possible solutions are proposed to overcome the issue.

Meeting Name

2020 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity, EMCSI 2020 (2020: Jul. 27-31, Virtual)


Electrical and Computer Engineering

Keywords and Phrases

Conductor Loss; Internal Inductance; Per-Unit-Length Resistance; Signal Integrity; Skin Effect; Surface Impedance Boundary Condition; Surface Roughness; Transmission Line

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2020 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

10 Sep 2020