Wang Yun-Hua

Electromagnetic scattering from two parallel 2D targets arbitrarily located in a Gaussian beam

In this paper based on the equivalence principle and the reciprocity theorem, the scattered field up to second-order by two parallel 2D targets arbitrarily located in a Gaussian beam is considered. The first-order solution can easily be obtained by calculating the scattered field from isolated targets when illuminated by a Gaussian beam. However, because of the difficulty in formulating the couple scattering field, it is almost impossible to find an analytical solution for the second-order scattered field if the shapes of 2D targets are not canonical geometries. In order to overcome this problem, in this paper, the second-order solution is derived by using the technique based on the reciprocity theorem and the equivalence principle. Meanwhile, the relation between the secondary scattered field from target #1 and target #2 is obtained. Specifically, the bi- and mono-static scattering of Gaussian beam by two parallel adjacent inhomogeneous plasma-coated conducting circular cylinders is calculated and the dependence of attenuation of the scattering width on the thickness of the coated layer, electron number density, collision frequency and radar frequency is discussed in detail.

Modified Two-Scale Model for Electromagnetic Scattering from the Non-Gaussian Oceanic Surface

Based on the skewness of sea waves, a modified two-scale model is developed for the non-Gaussian sea surface scattering. In this new model, a complementary term is added to the first-order scattering coefficient of the classical small perturbation method (SPM), the additional part is proportional to the surface bispectrum and it is the critical part in explaining the scattering difference between upwind and downwind observations. Meanwhile, the effects of the shadowing function of the anisotropic surface, the curvature of the surface are also taken into account. The numerical results show the theoretical estimates obtained are consistent with the experimental result, and the influence of the wind speed, the trend and the incident frequency on the backscattering coefficients from the non-Gaussian oceanic surface is discussed in detail.

Investigation on the coupling scattering model of a static conducting plate above the time-varying sea surface

Taking the advantage of a newly developed technique that uses the reciprocity theorem, the difficulty in formulating the scattered interaction between time-varying sea surface and a conducting plate is reduced. Meanwhile, a model is formulated for Doppler spectral shift of the coupling field, and is compared with the results simulated with the scattering field obtained in this work

Study on the electromagnetic scattering from non-Gaussian oceanic surface using the modified two-scale model

Base on the skewness of sea waves, a modified two-scale model is developed for non-Gaussian sea surface scattering. In this new model, a complementary term is added to the first-order scattering coefficient of the classical SPM (small perturbation method), the additional part is proportional to the surface bispectrum and it is the critical part in explaining the scattering difference between upwind and downwind observations. Meanwhile, the effects of the shadowing function of the anisotropic surface, the curvature of the surface are also taken into account. The numerical results show the theoretical estimates obtained are consistent with the experimental result, and the influence of the wind speed, the trend and the incident frequency on the backscattering coefficients from the non-Gaussian oceanic surface is discussed in details.

Study on the electromagnetic scattering interaction between a conducting plate and a 2D random rough surface

The electromagnetic scattering for the interaction between a perfectly conducting plate and a 2D conducting rough surface is investigated. Taking advantage of the reciprocity theorem, the difficulty in formulating the secondary scattered fields from the composite target reduces to the evaluation of an integral equation involving the polarization currents of the conducting plate and the scattered fields from the slightly rough surface. The induced polarization current on the conducting plate and the scattered fields from the slightly rough surface are evaluated using the physical optics (PO) method and the small perturbation method (SPM), respectively. The formulation for the backscattering field of the composite model is derived and the numerical results are presented. The dependence of the scattering cross section of the composite model on the position of the plate is discussed.