A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers

The study of scattered fields from nonspherical seatterers is becoming an important subject particularly in the area of theoretical modeling of microwave backscatter from vegetation. The generalized Rayleigh-Gans approximation has been widely used in the calculation of scattered fields from scattere...

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Main Authors: Koay, Jun Yi, Ewe, Hong Tat, Chuah, Hean Teik
Format: Article
Language:English
Published: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 2008
Subjects:
Online Access:http://shdl.mmu.edu.my/2753/
http://shdl.mmu.edu.my/2753/1/793.pdf
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author Koay, Jun Yi
Ewe, Hong Tat
Chuah, Hean Teik
author_facet Koay, Jun Yi
Ewe, Hong Tat
Chuah, Hean Teik
author_sort Koay, Jun Yi
building MMU Institutional Repository
collection Online Access
description The study of scattered fields from nonspherical seatterers is becoming an important subject particularly in the area of theoretical modeling of microwave backscatter from vegetation. The generalized Rayleigh-Gans approximation has been widely used in the calculation of scattered fields from scatterers where at least one of its dimensions is comparably smaller than the wavelength. In such calculations, far-field approximations are used, which are not accurate when the observation points are in the Fresnel and near-field regions of the scatterer. Hence, the effects of Fresnel phase and amplitude corrections for the scattered field of circular disks, needles, and cylinders have been examined and shown to be significant in the calculation of closely spaced scatterers. However, the effects of Fresnel corrections in the scattered fields from general ellipsoids and elliptic disks have not yet been studied. In this paper, the scattered fields from general ellipsoids and elliptic disks are, formulated based on the generalized Rayleigh-Gans approximation for cases with and without Fresnel corrections. Theoretical analysis shows that the Fresnel effects are important particularly at larger frequencies and at the null locations in the plots of the backscattering cross section. These effects become more important as the ellipticity of the scatterer increases. Comparisons with measurement data demonstrate that the calculated results with Fresnel corrections provide a better match compared with those without.
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spelling mmu-27532020-12-29T17:35:24Z http://shdl.mmu.edu.my/2753/ A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers Koay, Jun Yi Ewe, Hong Tat Chuah, Hean Teik T Technology (General) QA75.5-76.95 Electronic computers. Computer science The study of scattered fields from nonspherical seatterers is becoming an important subject particularly in the area of theoretical modeling of microwave backscatter from vegetation. The generalized Rayleigh-Gans approximation has been widely used in the calculation of scattered fields from scatterers where at least one of its dimensions is comparably smaller than the wavelength. In such calculations, far-field approximations are used, which are not accurate when the observation points are in the Fresnel and near-field regions of the scatterer. Hence, the effects of Fresnel phase and amplitude corrections for the scattered field of circular disks, needles, and cylinders have been examined and shown to be significant in the calculation of closely spaced scatterers. However, the effects of Fresnel corrections in the scattered fields from general ellipsoids and elliptic disks have not yet been studied. In this paper, the scattered fields from general ellipsoids and elliptic disks are, formulated based on the generalized Rayleigh-Gans approximation for cases with and without Fresnel corrections. Theoretical analysis shows that the Fresnel effects are important particularly at larger frequencies and at the null locations in the plots of the backscattering cross section. These effects become more important as the ellipticity of the scatterer increases. Comparisons with measurement data demonstrate that the calculated results with Fresnel corrections provide a better match compared with those without. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 2008-04 Article NonPeerReviewed text en http://shdl.mmu.edu.my/2753/1/793.pdf Koay, Jun Yi and Ewe, Hong Tat and Chuah, Hean Teik (2008) A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers. IEEE Transactions on Geoscience and Remote Sensing, 46 (4). pp. 1091-1103. ISSN 0196-2892 https://ieeexplore.ieee.org/abstract/document/4459185 10.1109/TGRS.2007.912446 10.1109/TGRS.2007.912446 10.1109/TGRS.2007.912446
spellingShingle T Technology (General)
QA75.5-76.95 Electronic computers. Computer science
Koay, Jun Yi
Ewe, Hong Tat
Chuah, Hean Teik
A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title_full A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title_fullStr A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title_full_unstemmed A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title_short A study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
title_sort study of fresnel scattered fields for ellipsoidal, and elliptic-disk-shaped scatterers
topic T Technology (General)
QA75.5-76.95 Electronic computers. Computer science
url http://shdl.mmu.edu.my/2753/
http://shdl.mmu.edu.my/2753/
http://shdl.mmu.edu.my/2753/
http://shdl.mmu.edu.my/2753/1/793.pdf