Coherent scattering from distributed targets

Based on the formulation for coherent backscattering from distributed targets previously published by the first author, this paper presents a unified formalism for incorporating the small amplitude, the small slope, the physical optics as well as a ldquotwo-scale modelrdquo approximation into analyses of backscattering by irregular air-dielectric interfaces. The distinguishing feature of this approach is that it takes explicit account of the antenna radiation properties and provides a direct means of numerically assessing the effects of spatial coherence of the surface irregularities on the receiver response. In particular, this leads to a generalization of the normalized backscattering cross-section which becomes dependent on both the antenna radiation properties and surface scattering characteristics. Numerical results obtained under the small amplitude approximation show that spatial coherence of the surface irregularities can lead to significant deviations from the classical Bragg scattering formula.