This paper is to present a new numerical method which can be used in computational electromagnetics in microwave remote sensing of random discrete medium embedded with irregular shape of scatterers. Current Radiative Transfer (RT) theoretical modeling is normally used to simulate wave propagation in the medium and wave scattering by basic shapes of scatterers, e.g., cylinder, disk, needle or sphere where the scattering of those scatterers was normally derived analytically with some assumption and approximation. To simulate the total backscattering coefficient from a layer of random medium, traditionally it was quite common that Mie phase matrix was used to compute the scattered fields of the scatterers which were approximated to be spherical shape. This has limited the extension of current theoretical model to be used to compute cases where irregular shape of scatterers are found embedded in the medium where many of the scatterers in real world are normally irregular or of complex shapes. As computational electromagnetics (CEM) becomes important in current modern engineering field, this provides an approach to model the scattering of such scatterers using CEM. In this paper, the Hierarchical Equivalent Source Algorithm (HESA) is used to compute scattered fields based on hierarchically structured equivalence sources residing within relaxed spherical equivalence surfaces. The 3D scatterer model used in HESA can be created using a 3D modeling software. After the 3D scatterer model is divided into smaller groups and each group is enclosed with a spherical equivalence surface, the scattered fields can be computed by equivalence source residing on smooth spherical equivalence surface through integral formulations. By incorporating HESA method into the current RT theoretical modeling, this can provide the improved theoretical model the capability to compute scattering of irregular or non-basic shape of scatterers embedded within the medium. The simulated scattering coefficient and extinction coefficient results from the newly implemented HESA based theoretical model were compared with those of current RT theoretical model and it was found that both results agreed with each other. The new model is then ready to be applied to simulate backscattering from a layer of earth medium for further theoretical analysis.


Electrical and Computer Engineering


National Natural Science Foundation of China, Grant FA2386-12-1-4082/FA2386-13-1-4140

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Article - Conference proceedings

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Publication Date

03 Nov 2016