• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.82-85
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• 2003

In this paper, we present the analysis of electromagnetic scattering from arbitrarily shaped three-dimensional conducting objects coated with a dielectric material. The integral equation treated here is the combined field integral equation. Numerical results of radar cross section for coated conducting structure are presented and compared with other available solutions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.105-109
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• 1987

A solution which combines ray and aperture integration(AI) techniques is presented for the problem of electromagnetic plane wave scattering by an open-ended, perfectly-conducting, semi-infinite parallel plate waveguide with a thin, uniform layer of lossy or absorbing material on its inner walls, and with a simple planar termination inside. Numerical results are given for the fields outside the waveguide.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.13-17
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• 1987

Electromagnetic wave scattering from the two-dimensional scatterer was calculated by the Boundary Element Method (BEM). For the circular cylindrical scatterer, the BEM solutions agreed very well with the analytic solutions. The rectangular dielectric cylinder was also treated in the case of the lossy scatterer and the lossy medium.

• 천문학회보
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• 제46권2호
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• pp.40.1-40.1
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• 2021

Hydrogen is the most abundant element in the universe, which is, in the cosmological context, attributed to its simplest structure consisting of a proton and an electron. Hydrogen interacts with an electromagnetic wave in astrophysical environments. Rayleigh scattering refers to elastic scattering, where the frequencies of the incident and scattered photons are the same. Rayleigh and resonance scattering is a critical role study Lyman Alpha objects in the early universe. The scattering causes the frequency and spatial diffusion of Lyα. In the case of Raman scattering, the energies of the incident and scattered photons are different. The photons near Lyβ convert to the optical photons near Hα through Raman scattering. The photon scattered by atomic hydrogen can carry both of the properties of the H I region and the emission region. I adopt a Monte Carlo approach to investigate the formation of the various spectral line features through Rayleigh and Raman scattering in highly thick media of atomic hydrogen. In this thesis, I present my works on radiative transfer involving the scattering processes between far UV photon and atomic hydrogen. I introduce scattering processes with atomic hydrogen and the spectral, spatial, and polarized information originating from the scattering.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.193-197
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• 2003

Radar target identification can be achieved by using various radar signatures, such as one-dimensional(1-D) range profile, 2-D radar images, and 1-D or 2-D scattering centers on a target. In this letter, five 1-D scattering center extraction methods are discussed - TLS(Total Least Square)-Prony, Fast Root-MUSIC (Multiple Signal Classification), Matrix-Pencil, GEESE(GEneralized Eigenvalues utilizing Signal-subspace Eigenvalues), TLS-ESPRIT(Total Least Squares - Estimation of Signal Parameters via Rotational Invariance Technique), These methods are compared in the context of estimation accuracy as well as a computational efficiency using a noisy data. Finally these methods are applied to the target classification experiment with the measured data in the POSTECH compact range facility.

• 한국전자파학회논문지
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• 제27권5호
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• pp.463-470
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• 2016

본 논문에서는 다중 편파(polarimetry) 데이터를 이용한 산란점(scattering center) 추출 알고리즘을 소개하고자 한다. 산란파 계산을 위해 상용 툴인 VIRAF(virtual aircraft framework)의 물리 광학법(Physical Optics: PO)/물리광학 회절이론(Physical Theory of Diffraction: PTD)을 사용하여 표적 표면과 모서리에 의한 산란을 각각 계산하였다. 또한, 단위 변환(unitary transformation)을 이용하여 선형 기저(linear basis) 기반 4-채널 데이터를 수평/수직-좌원형 기저(horizontal/vertical-circular basis) 2-채널 데이터로 변환하였고, 그 결과 데이터를 코히런트하게 압축할 수 있었다. 스펙트럼 추정 방법(spectral estimation technique)에 하나인 2차원 RELAX 알고리즘을 사용하여 산란점(scattering center) 추출을 하였고, 편파 방향과 관측각도 변화에 따른 산란현상을 각각 분석하였다.

• 한국전자파학회논문지
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• 제10권3호
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• pp.449-459
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• 1999

전파흡수체의 전자파산란 문제는 전송선로 근사방법과 유효매질 이론을 적용하여 매우 간단하게 표현할 수 있다. 이러한 방법은 전자장 수치해석 방법이 엄청난 계산이 필요한 것에 비해 매우 직관적이고, 간단하므로 전파흡수체 설계에 널리 사용되어져 왔다. 이 논문에서는 이러한 방법 자체가 가지는 근사의 한계 때문에 발생하는 적용한계를 유한요소법을 이용하여 검토하였다. 전송선로 근사방법은 λ 2p인 영역(여기에서, p는 전파흡수체의 배열주기, λ는 관심주파수 상한에서의 파장)에서 유효하다. 따라서 높은 물성을 갖거나 물리적 크기가 큰 구조의 전파흡수체는 흔히 이러한 조건을 만족치 않으며, 전자파 산란을 직접 수치해석적으로 계산해야 한다.

• Journal of electromagnetic engineering and science
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• 제3권2호
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• pp.133-139
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• 2003

The nonuniqueness of a mathematically rigorous solution to 2-dimensional inverse scattering problems is explained in a limiting view of the numerical calculations based on the spectral-domain moment method. It is illustrated that its theoretical uniqueness cannot be assured even by performing additional measurements of the scattered fields not only along multiple lines but also with angular/frequency-diversities. In a real situation, however, computational error and measurement noise are inevitable. Those limitations render it meaningless to controvert the existence of a theoretically rigorous solution. Hence the most practical issue is how to remedy the instability of its practically approximate solution.

• 한국전자파학회논문지
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• 제15권8호
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• pp.794-800
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• 2004

본 논문에서 TM 파가 입사할 때 얇은 유전체 strip의 산란특성에 대한 새로운 근사식을 구했다. 구한 식은 uniform하다. 즉 이 식은 어떠한 입사각 또는 관측점, 유전률, strip의 두께 등 모든 경우에 사용할 수 있고 다른 수치해석 방법, MoM을 이용하여 구한 식의 정확도를 여러 경우에 관해 검사해 보았다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.143-148
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• 2005

The objective of this study is to estimate RF signal strength over sea and land surfaces. For this work we calculated scattering by land with DEM(Digital Elevation Model) and sea surface with RMS surface height. and we selected two area inland and sea shore as RX point. And for each area, we get VV-pol and HH-pol characteristic of scattering at 2.2GHz.