Fast Frequency-Domain Modeling of Return Stroke Including Influence of Lossy Ground

A constitutive integral equation (CIE) formulation is proposed to model the lightning return stroke. From the CIE, the electromagnetic field radiated by the return stroke considering the lossy ground is determined by using the moment method (MM). To implement a fast numerical and rigorous approach, an exact image theory is first employed to accelerate the computation of Sommerfeld integral, and a translational mesh is then constructed under the thin-wire approximation. Such grid representation and the convolution properties of the integral kernel equip the fast Fourier transform to have the ability to efficiently solve the MM matrix equations. The feasibility and merits of the proposed method are positively confirmed by the comparison of its performances with those of an existing one on a case study.