摘要：

Using the full wave approach, the single and the double scattered electromagnetic fields from deterministic one dimensionally rough surfaces are computed. Full wave expressions for the single and the double scattered far fields are given in terms of multidimensional integrals. These integrals are evaluated using a supercomputer*. Applying the steepest descent approximation to the double scattered fields expression, the dimension of the integrals are reduced from four to two in the case of one dimensionally rough surfaces. It is shown that double scatter in the backward direction is significant only for near normal incidence when the rough surface is highly conducting and its mean square slope is very large. Even for one dimensionally rough surfaces, depolarization occurs when the reference plane of incidence is not parallel to the local planes of incidence and scatter. A geometrical optics approximation is used to interpret the results of the doubly scattered fields for normal incidence near backscatter. The physical interpretation of the results could shed light on the observed fluctuations in the enhanced backscatter phenomenon as the angle of incidence increases from near normal to grazing angles. For surfaces with large mean square slopes, it is found that the double scattered fields are large in the near specular direction. The results show that multiple scattering strongly depends upon the slope of the rough surface, the angle of incidence, and the conductivity of the rough surface. The analysis is extended to the two dimensional deterministic rough surfaces. Full wave expression for double scatter from the two dimensional surfaces is given in terms of four dimensional integrals.

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