Convergence analysis of integral equations for characterization of RF channels

The main concern of the present work is to investigate the convergence of the electric and magnetic field integral equations (EFIE and MFIE) adopted in the characterization of radio wave propagation over irregular terrains. The terrain irregularities are smooth, such that back-scattering is neglected and a recursive technique is used to determine the equivalent currents. Due to the near-grazing incidence and the vertical polarization of the incident field, the terrain can be considered an open surface made of a perfect magnetic conductor. This approach leads toward an equivalent problem that, in principle, can not be solved by the EFIE, a fact apparently overlooked in the literature. This may explain why the MFIE provides accurate results with a smaller number of basis functions than the EFIE.