The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
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A Numerical Study of Low Grazing Angle Backscattering from Random Rough Surfaces

不規則 粗面에서 저입사각 후방산란에 관한 수치해석

  • Kwang-Yeol Yoon (Department of Electronic Engineering, Keimyung University)
  • Published : 2002.07.01
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Abstract

We have numerically analyzed the electromagnetic wave scattering from randomly rough dielectric surfaces by using the finite volume time domain (FVTD) method. We have then shown that the present method yields a reasonable solution even at low-grazing angle (LGA). It should be noted that the number of sampling points per wavelength should be increased when more accurate numerical results are required, which fact makes the computer simulation impossible at LGA for a stable result. However, when the extrapolation is used for calculating the scattered field, an accurate result can be estimated. If we want to obtain the ratio of backscattering between the horizontal and vertical polarization, we do not need the large number of sampling points. The results are compared with the experimental data.

맥스웰방정식의 직접해인 FVTD(Finite Volume Time Domain)법을 이용하여, 저입사시의 불규칙 조면에서의 전자파 산란 문제를 수치해석 하였다. FVTD댑은 복잡한 구조의 전자파의 산란문제에 대해서 개발된 시간영역에 의한 수치해석법이며, 종래의 FDTD(Finite Difference Time Domain)법 보다 임의형태의 경계문제를 쉽게 다룰 수 있는 이점을 가지고 있다. 그러나 산란물체의 형태가 아주 복잡하고 정도를 문제삼을 경우 FVTD법에서는 셀 사이즈(cell size)를 충분히 세분화 할 필요가 있다. 그 경우 셀 사이즈에 의한 수치해의 수속성을 검토하고, 외삽법(extrapolation method)을 이용해서 간단하고 정확한 후방산란계수를 측정하는 방안을 제시했다. 더욱이 취급하는 편파의 상이를 특징짖는 레이다 단면적의 편파비에 대해서 입사각(grazing angle) 이 10도 이하의 해면 레이다의 실험결과와 비교하여, FVTD법의 수치계산 결과가 실측치와 잘 일치하는 결과를 제시했다.

Keywords

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