Study On Electromagnetic Scattering Characteristic And Visualization Of The Rough Surface And Vegetation

The dissertation presents systemic theoretical studies on the electromagnetic (EM) scattering by rough surface and vegetation. The approximate method and numerical method are applied to calculate the EM scattering from 1-D and 2-D rough surface. And the EM scattering of vegetation is investigated by the vector radiative transfer equation (VRT) and Monte-Carlo methods. Finally, we developed the visualization software on the EM scattering from the ground and vegetation. The main works are as follows:1. This paper begins by describing the rough surface of the relevant statistical concepts. The 1-D rough surface is simulated by the Monte Carlo method, and the 2-D rough surface is generated by the finite impulse response filter (FIR) theory combined with the fast Fourier transform (FFT) method.2. The electromagnetic scattering characteristic of` the 1-D and 2-D rough surface is studied by the Kirchhoff approximation (KA), and the dielectric properties of the actual land surface is analyzed, in addition, the scattering coefficient of the land surface is calculated.3. The method of moment (MOM) is adopted to compute the electromagnetic scattering of 1-D PEC and dielectric rough surface. The fast multipole method (FMM) is also presented to reduce the computation time and save the memory cost. The incident tapered plane wave in MOM method for scattering of rough surface is introduced into the classical KA method. Moreover, to obtain a high accuracy, the shadowing effect is also taken into account to modify the classical KA.4. Based on the Michigan Microwave Canopy Scattering (MIMICS) forest model, the two-layered random model composed of the vegetation and ground is established. The backscattering characteristic of two-layered vegetation is calculated by the zero-order and first-order solution of the VRT. And the backscattering enhancement of two-layered vegetation model is also analyzed by the Monte-Carlo method.5. Finally, according to the theoretical basis of the above-mentioned works, and the electromagnetic methods available in our laboratory, the visualized software on the electromagnetic scattering of the ground and vegetation is developed, which provides a convenient and practical software system for the non-professional staff engaged in electromagnetic fields.