A further study of the IEM surface scattering model
A further study of the IEM surface scattering model
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DOI：
10.1109/igarss.1996.516906
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发表时间：
1996-05
期刊：
影响因子：
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通讯作者：
C. Hsieh;A. Fung;G. Nesti;A. Sieber;P. Coppo
中科院分区：
文献类型：
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作者：
C. Hsieh;A. Fung;G. Nesti;A. Sieber;P. Coppo
基于一对控制表面电流的积分方程的近似解，建立了IEM表面散射模型。在导致近似的假设中，使用了频谱形式的绿色函数的简化表达式。特别是，有人认为，在两个表面点的表面高度的差异的绝对值出现在相位的绿色的功能可以忽略不计。这个论点是通过注意到（i）如果两个点靠近在一起，高度的差异应该很小，（ii）如果两个表面点相距很远，两个点之间的相关性应该可以忽略不计，因此不会对散射功率有显著影响。从数学上讲，没有理由做出这种假设，而且来自两个既不近也不远的表面点的贡献是否总是可以忽略也是值得怀疑的。在本文中，作者想删除这个假设，保留这个相位项，并检查散射计算的差异，没有它。它被发现，在所有情况下，考虑现有的IEM模型在单次散射给出了令人满意的预测。然而，在多重散射计算中，不可能忽略这个相位，特别是对于粗糙度较大的表面。该模型的应用程序从已知的粗糙的电介质表面的散射在EMSL的JRC在Ispra获得的示出和实现良好的协议。进一步应用到一个大的斜坡表面，导致后向散射增强也给出了良好的协议与数据。
The IEM surface scattering model was developed based on an approximate solution of a pair of integral equations governing the surface current. Among the assumptions leading to the approximation is the use of a simplified expression for the Green's function in spectral form. In particular, it was argued that the absolute value of the difference in the surface heights at two surface points appearing in the phase of the Green's function can be ignored. This argument was arrived at by noting that (i) if the two points are close together, the difference in heights should be small and (ii) if the two surface points are far apart, there should be a negligible amount of correlation between the two points and hence will not contribute significantly to the scattered power. Mathematically, there is no reason to make this assumption and it is also questionable whether the contribution from two surface points that are neither near or far can always be ignored. In this paper the authors want to remove this assumption by keeping this phase term and examine the difference in scattering calculations with and without it. It is found that in all cases considered the existing IEM model gives satisfactory predictions in single scattering. However, in multiple scattering calculations it is not possible to ignore this phase especially for surfaces with large roughness. An application of this model to scattering from known rough dielectric surfaces acquired at the EMSL of the JRC at Ispra is shown and good agreements are realized. Further application to a large slope surface that causes backscattering enhancement also gives good agreement with data.