二维粗糙面的多次散射和遮蔽效应研究

利用基尔霍夫近似研究了表面均方根斜率较大的二维粗糙面的多次散射问题。在多次散射理论中,随机粗糙面的总散射功率不仅与单次散射波有关,而且还取决于多次散射波。通过将格林函数做平面波展开的方法,二阶散射系数分解成与同向波和反向波有关的两部分,同向和反向分别是按单次散射场和其共轭场的耦合方式而划分的两种不同情况。引入考虑多次散射的遮蔽函数来修正掠入射情况下的散射系数,并将计算范围扩展到均方根斜率各向异性的二维粗糙面。将考虑多次散射的数值计算结果与前后向迭代方法的数值结果做了比较,两种方法的计算结果基本一致。

Study on the multiple scattering and shadowing effect from the two- dimensional rough surface

Multiple scattering from two-dimensional rough surface with large surface root mean square(RMS) slope is studied with Kirchhoff approximation.For the multiple scattering theory,the total scattered power from a random rough surface is contributed to,not only by single scattered waves,but also by those multiple scattered waves.With the plane wave representation of the Green's function,the second-order scattered coefficients are divided into two components related to the coincidental waves and the anti-coincidental waves,which are dependent on the relationship between the single scattered field and its conjugate.In addition,a shadowing function applicable to multiple scattering is taken into account,which extends the calculation to the surface with anisotropic slope distribution.In comparison of the numerical results of total multiple scattering with the forward-backward method,excellent agreement is obtained.