An Improvement of a Conductor Subdivision Method for Calculating the Series Impedance Matrix of a Transmission Line Considering the Skin and Proximity Effects

This paper describes an improvement of a conductor-subdivision-based method for calculating the frequency-dependent series impedance matrix of arbitrary cross-section conductors considering both skin and proximity effects. Analytical skin-effect formulas are available, but they are only for some simple conductor shapes and the proximity effect is ignored. Conductor-subdivision-based approaches can take into account both skin and proximity effects and are applicable to arbitrary cross-section conductors. However, at high frequencies where skin depth becomes very small, the subdivision-based approaches require an unrealistic number of subdivision. The proposed improvement assumes a current distribution obtained by an analytical skin-effect formula at surface subconductors for accurately representing the skin effect at high frequencies. Numerical examples show that the proposed improvement accurately reproduces the skin and proximity effects with a small number of subdivision even at high frequencies.