• Title, Summary, Keyword: Electromagnetic Scattering

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New Resonance Scattering Theory of Electromagnetic Waves for a Homogeneous Dielectric Cylinder (원통형 유전체에 대한 전자기파의 새로운 공진산란 이론)

  • 정용화;안창희;최명선
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.332-336
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    • 2001
  • The new RST is recently developed by the product expansion of the scattering functions in the field of acoustics. The new formulation suggests that the scattering coefficients consist of resonance, non-resonance, and their interactional components. In the scattering problems of acoustic waves, the moduli and phase of the resonance coefficient are obtained the appropriate results through the new RST. In our recent works the new RST was successfully applied to the scattering problem of electromagnetic waves for coated conducting cylinder and sphere. In this paper, the new RST is applied to the 2-dimensional scattering problem of electromagnetic waves for a homogeneous dielectric cylinder, and the numerical results are compared with the previous RST.

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New Resonance Scattering Theory of Electromagnetic Waves for a Homogeneous Dielectric Cylinder (원통형 유전체에 대한 전자기파의 새로운 공진산란 이론)

  • 정용화;안창회;최명선
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.1
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    • pp.87-93
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    • 2002
  • The previous RST postulates that the scattering field, within each modal partial wave, comprise of the resonance and the background components. The new RST is recently developed by the product expansion of the scattering functions in the field of acoustics. The new formulation suggests that the scattering coefficients consist of resonance, non-resonance, and their interactional portions. In the scattering problems of acoustic waves, the moduli and phase of the resonance coefficient are obtained correctly by the new RST. In our recent works the new RST was successfully applied to the scattering problem of electromagnetic waves for coated conducting cylinder and sphere. In this paper, the new RST is extended to the 2-dimensional scattering problem of electromagnetic waves for a homogeneous dielectric cylinder, and the numerical results are compared with the previous RST.

Line-Source Scattering from Slant Strips

  • Ock, Jang-Soo;Eom, Hyo-Joon
    • Journal of electromagnetic engineering and science
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    • v.9 no.4
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    • pp.229-231
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    • 2009
  • Electromagnetic scattering from slant strips excited by a line source is investigated. Boundary conditions are applied to obtain simultaneous equations for discrete modal coefficients. Computations are performed to illustrate the effects of line-source scattering on radiation patterns.

Numerical Analysis of Back Scattering from a Target over a Random Rough Surface Using DRTM

  • Yoon, Kwang-Yeol
    • Journal of electromagnetic engineering and science
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    • v.10 no.2
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    • pp.61-66
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    • 2010
  • This paper is concerned with an analysis of the back scattering of electromagnetic waves from a target moving along random rough surfaces such as the desert, and sea. First, the discrete ray tracing method(DRTM) is introduced, and then, this method is applied to the back scattering problem in order to investigate the effect of the back scattering from random rough surfaces on the electric field intensities. Finally, numerical examples of various height deviations of the Gaussian type of rough surfaces are shown. It is numerically demonstrated that the back scattering is dominated by the diffractions related to the reflections from the random rough surfaces.

Integral Transforms in Electromagnetic Formulation

  • Eom, Hyo Joon
    • Journal of electromagnetic engineering and science
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    • v.14 no.3
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    • pp.273-277
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    • 2014
  • In this research, integral transform technique for electromagnetic scattering formulation is reviewed. Electromagnetic boundary-value problems are presented to demonstrate how the integral transforms are utilized in electromagnetic propagation, antennas, and electromagnetic interference/compatibility. Various canonical structures of slotted conductors are used for illustration; moreover, Fourier transform, Hankel transform, Mellin transform, Kontorovich-Lebedev transform, and Weber transform are presented. Starting from each integral transform definition, the general procedures for solving Helmholtz's equation or Laplace's equation for the potentials in the unbounded region are reviewed. The boundary conditions of field continuity are incorporated into particular formulations. Salient features of each integral transform technique are discussed.

Scattering Model for Electrical-Large Target Employing MLFMA and Radar Imaging Formation

  • Wu, Xia;Jin, Yaqiu
    • Journal of electromagnetic engineering and science
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    • v.10 no.3
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    • pp.166-170
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    • 2010
  • To numerically calculate electromagnetic scattering from the electrical-large three-dimensional(3D) objects, the high-frequency approaches have been usually applied, but the accuracy and feasibility of these geometrical and physical optics(GO-PO) approaches, to some extent, are remained to be improved. In this paper, a new framework is developed for calculation of the near-field scattering field of an electrical-large 3D target by using a multilevel fast multipole algorithm(MLFMA) and generation of radar images by using a fast back-projection(FBP) algorithm. The MPI(Message Passing Interface) parallel computing is carried out to multiply the calculation efficiency greatly. Finally, a simple example of perfectly electrical conducting(PEC) patch and a canonical case of Fighting Falcon F-16 are presented.

Development of a radar scattering model for forest canopies (숲의 산란계수 계산 모델 개발)

  • Lee, Sung-Hwa;Oh, Yi-Sok
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.38-42
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    • 2003
  • In this paper, a radar scattering model for forest canopies has been developed based on an empirical rough surface scattering model and the radiative transfer theory. Leaves in the forest canopy are modeled by rectangular resistive sheets, brunches and trunks are modeled by cylinder, which sizes and orientations are randomly distributed. The scattering model has been verified with the measurement data of JPL/AirSAR system.

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Analysis of Electromagnetic Wave Scattering from a Sea Surface Using a Monte-Carlo FDTD Technique

  • Choi Dong-Muk;Kim Che-Young;Kim Dong-Il;Jeon Joong-Sung
    • Journal of electromagnetic engineering and science
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    • v.5 no.2
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    • pp.87-91
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    • 2005
  • This paper presents a Monte-Carlo FDTD technique to determine the scattered field from a perfectly conducting surface like a sea surface, from which the useful information on the incoherent pattern tendency could be observed. A one-dimensional sea surface used to analysis scattering was generated using the Pierson-Moskowitz model. In order to verify the numerical results by this technique, these results are compared with those of the small perturbation method, which show a good match between them. To investigate the incoherent pattern tendency involved, the dependence of the back scattering coefficients on the different wind speed(U) is discussed for the back scattering case.

Solution of the Inverse Electromagnetic Scattering Problem for Cylindrical Objects by Using the Resonance Scattering Ttheory (공진산란이론을 이용한 원통형 산란체에 대한 전자기파문제의 역산란 이론)

  • Jung, Yong-Hwa;Jeon, Sang-Bong;Ahn, Chang-Hoi
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.3
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    • pp.142-148
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    • 2006
  • The resonances that contain the information on the properties of the scattering target can be used for target reconstruction approaches. The inverse scattering theory for the resonances has been applied to the problems of the scattering for a spherical, cylindrical dielectric objects and dielectrically coated conductors, shown reasonable results. Though by using this method the thickness and the dielectric constants of the target can be obtained from a determination of the spacing and of the widths of the scattering resonances, the radius of the target should be given. In this paper, we suggest the improved inverse theory combined with the resonance scattering theory to obtain the radius in addition to the dielectric constant of the target. The applications of this method for scattering problems of electromagnetic waves from cylindrical targets were accomplished, and it shows its validity.

A Simple Microwave Backscattering Model for Vegetation Canopies

  • Oh Yisok;Hong Jin-Young;Lee Sung-Hwa
    • Journal of electromagnetic engineering and science
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    • v.5 no.4
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    • pp.183-188
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    • 2005
  • A simple microwave backscattering model for vegetation canopies on earth surfaces is developed in this study. A natural earth surface is modeled as a two-layer structure comprising a vegetation layer and a ground layer. This scattering model includes various scattering mechanisms up to the first-order multiple scattering( double-bounce scattering). Radar backscatter from ground surface has been modeled by the polarimetric semi-empirical model (PSEM), while the backscatter from the vegetation layer modeled by the vector radiative transfer model. The vegetation layer is modeled by random distribution of mixed scattering particles, such as leaves, branches and trunks. The number of input parameters has been minimized to simplify the scattering model. The computation results are compared with the experimental measurements, which were obtained by ground-based scatterometers and NASA/JPL air-borne synthetic aperture radar(SAR) system. It was found that the scattering model agrees well with the experimental data, even though the model used only ten input parameters.