• 한국전자통신학회논문지
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• 제14권6호
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• pp.1031-1036
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• 2019

본 연구는 드론 및 능동 빔패턴 측정장치를 활용하여 초단파레이다용 배열안테나의 빔패턴 측정내역에 대해서 기술하였다. 아직 국내에서는 크기가 큰 초단파대역용 안테나의 빔패턴을 측정하기 위한 무반사실이 없는 상황이다. 본 연구는 개발된 초단파레이다의 안테나 빔패턴 특성을 시험하기 위하여 드론에 능동 빔패턴 측정장치 및 수신안테나를 장착하여 안테나 빔패턴 특성을 시험하였다. 안테나에 대한 사전 시뮬레이션 분석결과와 측정된 결과를 비교하였을 때 빔폭 특성 및 부엽특성이 만족함을 확인 할 수 있었다. 향후 드론 및 능동 빔패턴 측정장치를 활용한 안테나 빔패턴 측정기술을 통하여 안테나 크기가 큰 저주파대역 레이다용 배열안테나의 빔패턴 측정 기술을 활용할 예정이다.

• 한국레이저가공학회지
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• 제18권3호
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• pp.6-8
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• 2015

Finishing process includes deburring, polishing and edge radiusing. It improves the surface profile of specimen and eliminates the alien substance on surface. Deburring is the elimination process for debris of edges. Polishing lubricates surfaces by rubbing or chemical treatment. There are two types for electron finishing. The one is using pulse beam. The other is using the convergent and scanning electron beam. Pulse type device appropriates the large area process. But it does not control the beam dosage. Scanning type device has advantages for dosage control and edge deburring. We design the convergence and scan type. It has magnetic lenses for convergence and scan device for scanning beam. Magnetic lenses consist of convergent and objective lens. The lenses are designed by the specification(beam size and working distance). In this paper, we evaluate the convergence performance by pattern process. Also, we analysis the results and important factors for process. The important factors for process are beam size, pressure, stage speed and vacuum. These results will be utilized into systematizing pattern shape and the factors.

• 한국정밀공학회지
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• 제15권10호
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• pp.156-164
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• 1998

Electronic Speckle Pattern Interferometry(ESPI) has been used to measure surface deformations of engineering components and materials in industrial areas. ESPI, a non-contact and non-destructive technique, is capable of providing full-field results with high spatial resolution and high speed. One of the important application using electronic speckle pattern interferometry is electronic speckle contouring of a diffused object for 3-D shape analysis and topography measurement. Generally the electronic speckle contouring is suitable for providing measurement range from millimeters to several centimeters. In this study, we introduce the contouring method by modified dual-beam speckle pattern interferometer and the shift of the two illumination beams through optical fiber in order to obtain the contour fringe patterns. We also describe formation process of depth contour fringes and grid contour fringes by shifting direction of the two illumination beams. Before the experiments, we performed the geometric analysis for dual-beam-shifted ESPI contouring, and then, the electronic speckle contouring experiment with various specimens. For quantitative analysis of the contour fringes, we used 4-frame phase shifting method with PZT Finally, good agreement between the geometric analysis and experimetal results is obtained.

• 한국산업융합학회 논문집
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• 제4권2호
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• pp.149-155
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• 2001

The use of primitive cell volume and zero order Laue (ZOLZ) pattern is proposed to identify phase in a complex microstructure. Single convergent beam electron pattern containing higher order Laue zone ring from a nanosized region is sufficient to calculate the primitive cell volume of the phase, while ZOLZ pattern is used to determine the zone axis of the crystal. A computer program is used to screen out possible phases from the value of measured cell volume from convergent beam electron diffraction (CBED) pattern. Indexing of ZOLZ pattern follows in the program to find the zone axis of the identification from a single CBED pattern. An example of the analysis is given from the rapidly solidified $Al-Al_3Ti$ system.

• 한국ITS학회 논문지
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• 제3권1호
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• pp.21-30
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• 2004

본 논문에서는 자동요금 징수 시스템(ETCS : Electronic Toll Collection System)의 RSE와 OBU 간의 RF link설계와 도로의 폭과 진행 방향 길이에서 적절한 통신 영역을 얻기 위해 요구되는 안테나의 빔 패턴 특성을 분석하였다. 이 과정은 능동형 DSRC를 기반으로 하는 ITS 서비스의 시스템 요구 규격을 결정하기 앞서 수행되어져야 하며, ETCS 기지국 설계 및 구축에서 가장 기본적이고 중요한 기술적 분석을 위하여 고찰하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.397-401
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• 1995

ESPI(Electronic Speckle Pattern Interfermetry) is an optical technique to measure surface deforamtion of engineering components and materials in industrial ares. This optical method is capable of providing full-field results with high spatial resolution, high speed and is the non-contact technique. One of important application aspects using electronic speckle pattern interferometry is to generate contours of a diffuse object in order to provide data for 3-D shape analysis and topography measurement. The contouring method by modified dual-beam speckle pattern interferometry is proposed. We introduce a shift of the illumination beams through optical fiber in order to obtain the contour fringe patterns. The speckle pattern correlation technique is suitable for providing measurement range from millimeters to several centimeters. The complete geometric analysis of the contoretical and experimental results are obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.593-597
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• 2005

FIB equipment can perform sputtering and chemical vapor deposition simultaneously. It is very advantageously used to fabricate a micro structure part having 3D shape because the minimum beam size of ${\phi}$ 10nm and smaller is available. Currently FIB is not being applied in the fabrication of this micro part because of some problems to redeposition and charging effect of the substrate causing reduction of accuracy with regards to shape and productivity. Furthermore, the prediction of the material removal rate information should be required but it has been insufficient for micro part fabrication. The paper have the targets that are FIB-CVD characteristic analysis and minimum line pattern resolution achievement fur 3D micro fabrication. We make conclusions with the analysis of the results of the experiment according to beam current, pattern size and scanning parameters. CVD of 8 pico ampere shows superior CVD yield but CVD of 1318 pico ampere shows the pattern sputtered. And dwell time is dominant parameter relating to CVD yield.

• 한국광학회지
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• 제31권6호
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• pp.268-273
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• 2020

레이저 빔이 산란 매질에서 반사될 때 발생하는 스펙클 패턴을 모니터링함으로써 산란 매질에 입사하는 레이저 빔들의 결맞는(coherent) 결합 상태를 분석하고자 하였다. 이를 위하여 가간섭성이 높은 3개의 시준 레이저 광원을 자유공간에서 렌즈를 이용하여 무작위 표면특성을 가진 산란목표물(scattering target)에 집속한 후, 되돌아오는 빔의 스펙클 패턴을 푸리에 영역에서 살펴보았다. 목표물에 입사하는 단일 레이저 빔의 크기변화 및 3개 결맞는 레이저 빔 간의 공간적인 빔결합 정도에 따라 스펙클 패턴의 평균적인 크기가 변하게 되는데, 이를 푸리에 영역에서 분석함으로써 결맞음 빔결합의 효율을 판별할 수 있는 단일 모니터링 변수를 도출할 수 있었다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.239-244
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• 1998

ESP(Electronic Speckle Pattern Interferometry) is an optical technique to measure deforamtion of engineering components and materials in industrial areas. ESPI, a non-contact and non-destructive measuring method, is capable of providing full-field results with high spatial resolution and high speed. One of important application aspects using electronic speckle pattern interferometry is to generate contours of a diffuse object in order to provide data for 3-D shape analysis and topography measurement. The electronic speckle contouring is suitable for providing measurement range from millimeters to several centimeters. In this study, we introduce the contouring method by modified dual-beam speckle pattern interferometer and a shift of the two illumination beams through optical fiber in order to obtain the contour fringe patterns. Before the experiments, we performed the geometric analysis for dual-beam-shifted ESPI contouring. And by this geometric analysis, we performed the electronic speckle contouring experiment. We used 4-frame phase shifting method with PZT for quantitative analysis of contour fringes. Finally, we showed good agreements between the geometric analysis and experimental results.

• 한국전자파학회논문지
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• 제9권2호
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• pp.141-148
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• 1998

빔 성형 안테나를 개발하기 위해서 변형된 전송선로형 안테나(MTLA)의 둘레 및 수평, 수직 소자 길이를 가변한다. 빔 틸트 특성의 검증을 위해 각각의 변형된 형상을 갖는 MTLA에 대한 수직면 방사패턴을 모먼트법으로 해석한다. 해석 결과로부터 구현될 수 있는 최대 빔 틸트는 주로 수직 소자길이에따라 결정된다는 사실올 확 인하였다. 최대 빔 틸트를 갖는 안테나를 셜게하고 입력 임피던스 및 방사 특성을 이론적으로 계산하고 실험에 의하여 확인하였다.