Thin-Wire Models for Inclined Conductors With Frequency-Dependent Losses

This paper presents the finite-difference time-domain (FDTD) thin-wire models of lossy wire structures with arbitrary inclination for transient analysis, which is difficult to address using the traditional FDTD methods. The frequency-dependent losses of the conductors are fully taken into account, and the vector fitting technique is applied to deal with frequency-dependent parameters for time-domain analysis. The bidirectional coupling within the lossy coaxial conductors is modeled. The currents in inner and outer conductors are not necessarily balanced. Three cases are presented for the investigation of wave propagation velocity, wave attenuation, and current distribution. These data are compared with analytical results and numerical results using other models. It is found that the proposed thin-wire models can depict the transient behaviors in the lossy inclined conductors with a velocity error of less than 1%, and an attenuation error of less than 1.5%.