• 제목/요약/키워드: dielectric cylinder

검색결과 38건 처리시간 0.025초

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

  • 정용화;안창희;최명선
    • 한국전자파학회:학술대회논문집
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    • 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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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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원통형 유전체 광 증폭기에 대한 연구 (Dielectric Cylinder Optical Amplifier)

  • 이성수
    • 한국광학회:학술대회논문집
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    • 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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    • pp.146-147
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    • 2000
  • The electromagnetic wave scattering from active objects has only recently attracted attention.$^{(1).(3)}$ Theoretical studies have considered normal-incidence plane-wave interactions with active dielectric cylinders with the prediction of large enhancements in the scattered field for bound mode structures. According to the theory of the electromagnetic wave scattering from a dielectric cylinder, the eigenvector solutions are discrete and have both guided (non-radiative) and leaky (radiative) mode solutions. By using an anti-guiding (leaky) structure instead of a guided structure and scattering at oblique incident angles near critical angle, the scattering resonances predicted by theoretical studies were obtained for the first time. A fine-grained scan of the plane-wave incident angle a reveals the existence of discrete scattering resonances. The diameter and real part of the index of refraction determine the resonant conditions and the imaginary part of the refractive index has a threshold value to make mode up for its radiation loss. The cross coupling between transverse electric (TE) and transverse magnetic (TM) modes is clearly detected for both active and passive scattering as theoretically expected. (omitted)

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Improvement of Heating Pattern in RF Hyperthermia -Simultaneous Application of Dielectric Heating and Induction Heating-

  • Sakakibara, Norifumi;Ochiai, Makoto;Hayakawa, Yoshinori
    • 한국의학물리학회:학술대회논문집
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    • 한국의학물리학회 2002년도 Proceedings
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    • pp.478-480
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    • 2002
  • Heating by RF wave is divided into dielectric heating and induction heating. Dielectric heating and induction heating from outside the body have the compensatory heating pattern. While surface fat layer is heated by dielectric heating, it is not heated by induction heating. While the peripheral part at the middle of the electrodes is not heated by dielectric heating, it is heated by induction heating. By the simultaneous application both modalities, heating pattern seems to be more uniform and improved. Computer simulation of Finite Element Method (FEM) using ANSYS was conducted to dielectric heating with the results of above-mentioned feature. Theoretical considerations by the uniform RF magnetic field in a cylinder and textbooks support the feature of the above-mentioned heating pattern of induction heating. Further computer simulation of FEM using ANSYS will be conducted to simultaneous application of dielectric heating and induction heating to verify and will be reported.

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유전체실린더로 둘러 싸인 완전 도체스트립에 의한 TM파의 산란 (TM Wave Scattering by the Perfectly Conducting Strip Loaded with a Dielectric Cylinder)

  • 김남태;이상설
    • 대한전자공학회논문지
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    • 제27권3호
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    • pp.7-12
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    • 1990
  • 상이한 유전율의 유전체실린더로 완전 도체스트립이 둘러 싸여 있을 때 도체스트립에 의한 산란현상을 해석하였다. 보조전자계를 도입하여 가역정리를 적용함으로서 미지전계에 대한 적분방정식이 유도되며 이는 적절한 경계조건에 의하여 등가행렬방정식으로 변형된다. 이 행렬방정식으로 부터 미지계수의 역행렬을 구함으로서 산란전자계가 결정된다. 본 논문에서 얻어진 결과는 특수한 경우로서 실린더의 유전율을 같게 했을때 기존의 연구결과와 잘일치한다.

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주기적인 구형격자로 로딩된 유전체 코팅된 도체 실린더의 복사 특성 (Radiation Characteristics of Dielectric-Coated Conducting Cylinder Loaded with Periodic Corrugation)

  • 김중표;손현
    • 한국전자파학회논문지
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    • 제11권3호
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    • pp.388-402
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    • 2000
  • 주기적인 구형격자를 갖는 유전체 코팅된 도체 실린더에 대해 무한 주기 구조와 유한 주기 구조에 대한 누설 파 안테나의 복사 특성을 이론적으로 해석하였다. 무한 주기 구조에 대하여는 모드 정합 법을 적용하여 해석하 였고, 유한 주기 구조에 대하여는 퓨리에 변환과 모드 전개를 사용하여 적분 방정식을 유도하고 선형 연립 방정 식을 얻는다. 구형격자의 폭, 깊이, 유전체 코팅두께, 도체 실린더의 반경, 유한 구형격자 개수의 영향이 위상 상 수, 누설 상수 및 복사패턴 등과 복사 특성에 미치는 영향을 조사하였고, 유한 주기 구조와 무한 주기 구조의 결 과를 비교하고 잘 일치함을 확인할 수 있었다. 균일 유한 주기 구형격자에 의한 높은 측엽을 줄이기 위해 안테나 의 전후단 부에 테이퍼링과 비균일 준주기 슬롯배열을 고려하였다. 또한 구형격자 표면파 안테나에 사용되는 구 형격자 주기. 폭, 깊이에 대해 테이퍼링을 통해 낮은 측엽을 갖는 endfire 복사패턴을 얻을 수 있었다.

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쌍이방성 매질 코팅 다층 원통에 의한 전자파 산란 해석[II] (EM wave scattering by bianisotropically coated multilayer cylinder with an impedance sheet[II])

  • 엄상진;윤중한;이화춘;곽경섭
    • 한국통신학회논문지
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    • 제26권4B호
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    • pp.391-399
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    • 2001
  • In this paper, electromagnetic wave scattering from a bianisotropicaly coated cylinder is formulated by using wave functions for bianisotropic media and boundary-value method. The cross section of the cylinder is made of a conducting core, a lossless dielectric layer which is both electrically magnetically bianisotropic, and a bianisotropic impedance sheet and a different uniaxial bianisotrpic coating. The solutions to arbitrary polarization angles are presented in two-dimensional. This paper presents and exact solution to the problem of scattering by a long composite circular cylinder using the boundary method. The validity of this solution is verified by comparing numerical results with those in literature. The numerical results for various geometrical and electrical parameters on bistatic scattering cross-section are presented.

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유전체 내의 두개의 빈 원기둥에 의해 산란된 전자파의 감쇄패턴 (attenuation pattern of the electromagnetic fields scattered by two empty circular cylinders in a dielectric medium)

  • 이택경;김세윤;라정웅
    • 전자공학회논문지A
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    • 제33A권4호
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    • pp.92-97
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    • 1996
  • The attenuation pattern of the E-polarized electromagnetic fields scattered by two empty circular cylinders in a dielectric medium is analyzed to calculate the effects of the inhomogenuity in hte background medium. Inthe amplitude pattern of the electromagnetic field scattered by one cylinder, double dips occur at the locations corresponding to its top and bottom boundaries. The distorton of the original double dip pattern is calculated when other air cavity approaches or its size increases.

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Influence of Tank Inner Side Dielectric Coating on the Particle Behaviour and Flashover Voltage in SF\ulcorner Gas Insulated System

  • Lee, Bang-Wook;Koo, Ja-Yoon
    • Journal of Electrical Engineering and information Science
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    • 제2권3호
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    • pp.77-81
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    • 1997
  • In his work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when the epoxy resin based dielectric coating was made on he inner side of outer electrode. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various sizes of Cu conducting particle were used under different gas pressures. In order to elucidate the coating effect on the gas insulation, different thickness of dielectric coating has been considered and then the lift-off voltage and flashover voltages have been measured. The results shown that the dielectric coating has a remarkable influence by restraining the movement of particle in GIS system, and thus GIS insulation reliability is noticeably improved.

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