DocumentCode :
896250
Title :
Bistatic Scattering and Emissivities of Lossy Dielectric Surfaces With Exponential Correlation Functions
Author :
Xu, Peng ; Tsang, Leung
Author_Institution :
Sch. of Electron. Inf., Wuhan Univ.
Volume :
45
Issue :
1
fYear :
2007
Firstpage :
62
Lastpage :
72
Abstract :
Bistatic scattering and emissivities of surfaces with exponential correlation functions are studied numerically for 2-D geometries in a numerical Maxwell model with 2-D simulations. Surfaces with exponential correlation functions are important for the active and passive microwave remote sensing of land surfaces. Because of the fine-scale features with large slopes of such surfaces, numerical accuracy, which is particularly important for the calculation of emissivity in passive remote sensing, is ensured by a variety of procedures in this paper. The rooftop function and Galerkin´s method with numerical integration of near-field impedance matrix elements are used. Cubic spline interpolation is employed to connect knots on random rough surfaces. Numerical accuracy convergence tests are performed for numerical solutions of Maxwell equations by varying the number of points from 13 to 103 points per wavelength in the dielectric medium corresponding to 50-400 points per free wavelength. Surface lengths of up to 100 and 200 free wavelengths and root mean square heights of up to 0.4 and 0.8 free wavelengths, respectively, are used at 5 and 10 GHz to capture all the essential features. Because of the large number of surface unknowns (up to 80 000), the multilevel UV method is further used to accelerate the matrix equation solver. Numerical results are illustrated for both bistatic scattering and emissivities as functions of frequencies and incidence and scattering angles for cases of interests in microwave remote sensing. Comparisons are made with the second-order small perturbation method and Kirchhoff´s approximation to reestablish the regimes of validity of these methods
Keywords :
Galerkin method; Maxwell equations; dielectric losses; electromagnetic wave scattering; emissivity; remote sensing; splines (mathematics); topography (Earth); 10 GHz; 5 GHz; Galerkin method; Kirchhoff approximation; Maxwell equations; bistatic scattering; cubic spline interpolation; dielectric medium; exponential correlation functions; land surface active microwave remote sensing; land surface passive microwave remote sensing; lossy dielectric surfaces; matrix equation solver; multilevel UV method; near field impedance matrix elements; numerical Maxwell model; numerical accuracy convergence tests; random rough surfaces; rooftop function; root mean square heights; second order small perturbation method; Dielectric losses; Geometry; Land surface; Moment methods; Numerical models; Passive microwave remote sensing; Rough surfaces; Scattering; Solid modeling; Surface roughness; Active remote sensing; electromagnetic scattering; fast solver; microwave emissivity; passive remote sensing; soil rough surface;
fLanguage :
English
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/TGRS.2006.883458
Filename :
4039639
Link To Document :
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