Scalar plane wave scattering from a thin film with two-dimensional fluctuation∗∗

∗∗ Part of this paper was presented at the 2006 Progress in Electromagnetics Research Symposium [1].

Abstract

This paper deals with a scalar plane wave scattering from a thin film with two-dimensional fluctuation by means of the stochastic functional approach. The refractive index of the thin film is written as a Gaussian random field in the transverse directions with infinite extent, and is invariant in the longitudinal direction with finite thickness. An explicit form of the random wavefield involving effects of multiple scattering is obtained in terms of a Wiener–Hermite expansion under small fluctuation. The first- and second-order incoherent scattering cross-sections are calculated numerically and illustrated in figures. In the incoherent scattering, scattering ring, quasi-anomalous scattering, enhanced scattering and gentle enhanced scattering may occur.

∗∗ Part of this paper was presented at the 2006 Progress in Electromagnetics Research Symposium [1].

Notes

∗∗ Part of this paper was presented at the 2006 Progress in Electromagnetics Research Symposium [1].

^†The absolute refractive index of a medium means the refractive index for refraction from the reference medium into that medium.

∗Numerical calculations for a random thin film having guided wave modes will be discussed elsewhere.

^†The random thin film given by (82) and (83) is a simple model of a partially turbulent atmosphere. Therefore, scattering from such a random thin film by scalar plane wave incidence can become a substitution of that by a TE-polarized EM wave incidence, if cross-polarized scattering can be neglected.

^†From numerical results of a 1D random slab[21], where the refractive index fluctuates only in the thickness direction, the optical theorem with the first three order Wiener kernels holds within an accuracy of about 0.4% for σ² < 0.02 at l = 10Λ.