Causality Analyzing for Transmission Line with Surface Roughness


Surface roughness of the conductor in transmission lines will introduce extra losses. The recently proposed Huray model is quite accurate for modeling these additional losses by changing R terms in RLGC models. However, only focusing on the loss modeling of the transmission line may lead to causality issues in time domain simulations. In this paper, the causality requirements of the RLGC models are theoretically analyzed firstly. Then, two solutions of the causality problems in Huray model-based transmission line with rough conductors modeling were proposed and compared. One of them is based on the numerical Hilbert transform, and the other one is analytically based on a complex-valued roughness factor. The causalities of those two solutions are validated by a time domain pulse through a transmission line. The results comparisons of the received pulse responses after the transfer functions show that both methods can improve the causality of the wave propagation term significantly, whereas the analytical solution has better performances and the numerical method has some limitations.

Meeting Name

2019 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMC+SIPI 2019 (2019: Jul. 22-26, New Orleans, LA)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory


This work was supported in part by the National Natural Science Foundation of China under Grant 61771425 and in part by the US National Science Foundation under Grant IIP-1440110.

Keywords and Phrases

Analytical Solutions; Causality; Conductor Roughness; Hilbert Transform; Transmission Lines

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2019 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jul 2019