Electromagnetic scattering by a layered earth with arbitrarily varying subsurface impedance


  • Samir F. Mahmoud


The problem of scattering of a plane electromagnetic wave from a two-layered earth with laterally varying substrate surface impedance is considered. A formal iterative solution which is applicable to any arbitrary profile of the substrate surface impedance is derived and is adapted for use of the fast Fourier transform (FFT) technique to obtain numerical results for the scattered fields and hence for the effective surface impedance and wave tilt. The aim is to study the effect of a finite lateral extent of an underground conducting layer, such as water, on the above quantities, which are measurable at the earth's surface. Numerical examples show that the effective surface impedance and wave tilt are good indicators of the variations in the substrate surface impedance.