Transient source current formulation for the analysis of arbitrarily shaped dielectric/conducting composite structures

In this paper, a novel time-domain integral equation (TDIE) approach is presented to analyze the transient electromagnetic response from three-dimensional dielectric/conducting composite structures. The composite bodies with different materials and conductor structures are considered as autonomous scattering objects. The scattered electromagnetic field is derived by superposition of the individual scatterers. The principal method is based on the application of electric and magnetic field boundary conditions on the surfaces of dielectric and conducting objects while considering the electric currents as unknowns. Triangular patches as well as quadrangular patches model the surfaces of the combined structure. The scattered electromagnetic fields inside and outside the combined structure depend only on the electric surface currents. This improves the post-processing time and complexity as compared with other methods using both equivalent electric and magnetic surface currents. To solve the resultant integral equations, the implicit method of moments is used. In our approach, the internal fields are independent of external currents and vice-versa, reducing the number of the matrix elements by considering them as zero.