A numerical simulation of scattering from one-dimensional inhomogeneous dielectric random surfaces
A numerical simulation of scattering from one-dimensional inhomogeneous dielectric random surfaces
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DOI：
10.1109/36.485120
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发表时间：
1996-03
期刊：
影响因子：
--
通讯作者：
K. Sarabandi;Y. Oh;F. Ulaby
中科院分区：
文献类型：
--
作者：
K. Sarabandi;Y. Oh;F. Ulaby
给出了非均匀介质粗糙表面散射问题的一种有效的数值解。非均匀介质随机表面代表一个裸露的土壤表面，被认为是由阻抗表面上大量随机定位的不同大小、形状和介电常数的介电峰组成的。含水率不均匀的土块和岩石用不均匀的介电峰来模拟，下伏的光滑湿土表面用阻抗面来模拟。利用精确像理论导出的格林函数，结合矩量法，得到了阻抗表面上组成介质峰的有效数值解。粗糙表面的散射场是通过将表面所有单个峰的散射场进行相干求和而得到的，忽略了峰间多次散射的影响。散射系数/spl σ //spl度/的统计特性是通过计算许多不同实现的表面散射场得到的。给出了几种不同粗糙度和介电常数随机表面的数值结果。通过将数值解与基于小摄动法和基于物理光学模型的均匀粗糙表面解进行比较，验证了数值解的正确性。该方法可用于研究无解析解的粗糙土壤表面的散射系数和相位差统计特性。
An efficient numerical solution for the scattering problem of inhomogeneous dielectric rough surfaces is presented. The inhomogeneous dielectric random surface represents a bare soil surface and is considered to be comprised of a large number of randomly positioned dielectric humps of different sizes, shapes, and dielectric constants above an impedance surface. Clods with nonuniform moisture content and rocks are modeled by inhomogeneous dielectric humps and the underlying smooth wet soil surface is modeled by an impedance surface. In this technique, an efficient numerical solution for the constituent dielectric humps over an impedance surface is obtained using Green's function derived by the exact image theory in conjunction with the method of moments. The scattered field from a sample of the rough surface is obtained by summing the scattered fields from all the individual humps of the surface coherently ignoring the effect of multiple scattering between the humps. The statistical behavior of the scattering coefficient /spl sigma//spl deg/ is obtained from the calculation of scattered fields of many different realizations of the surface. Numerical results are presented for several different roughnesses and dielectric constants of the random surfaces. The numerical technique is verified by comparing the numerical solution with the solution based on the small perturbation method and the physical optics model for homogeneous rough surfaces. This technique can be used to study the behavior of scattering coefficient and phase difference statistics of rough soil surfaces for which no analytical solution exists.