• 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.

• Transactions on Electrical and Electronic Materials
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• 제9권3호
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• pp.120-122
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• 2008

We have studied the tilt angle generation on the homeotropic polyimide (PI) surface using a low intensity ion beam source as a function of incident angle. An excellent LC alignment of nematic liquid crystal (NLC) on the PI surface with ion beam exposure for all incident angles was observed. The tilt angle of NLC on the homeotropic PI surface for all incident angles was from 90 to 88 degree was observed. Also the tilt angle of NLC on the homeotropic PI surface with ion beam exposure of 400 eV had a tendency to increase as ion beam energy incident angle become more instance from 45 degree. Finally, a good LC alignment thermal stability on the homeotropic PI surface with ion beam exposure can be achieved.

• Transactions on Electrical and Electronic Materials
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• 제7권6호
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• pp.305-308
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• 2006

We have studied liquid crystal (LC) aligning capabilities for homeotropic alignment and the control of tilt angles on the $SiO_{x}$ thin film by electron beam evaporation method. A high tilt angle of about $86.5^{\circ}$ was obtained, and also the suitable tilt angle of the NLC on the $SiO_{x}$ thin film at $20{\sim}50\;nm$ thickness with e-beam evaporation can be achieved. The uniform LC alignment on the $SiO_{x}$ thin film surfaces with electron beam evaporation can be achieved. It is considerated that the LC alignment on the $SiO_{x}$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_{x}$ thin film surface created by evaporation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.288-289
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• 2006

The tilt angle generation of nematic liquid crystal(NLC) on the homeotropic polyimide(PI) surface by the new Ion beam alignment method is studied. The tilt angle of NLC on the homeotropic PI surface for all incident angle is about 38and this has a stabilization trend. And the good LC alignment of the NLC on the PI surface by ion beam exposure of 45Incident angle was observed. Also the tilt angle of NLC on the homeotropic PI surface by ion beam exposure of 45Incident angle had a tendency to decrease as ion beam energy density increase. So we had known that pretilit angle could be controlled from verticality to horizontality.

• 전기학회논문지
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• 제61권11호
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• pp.1668-1670
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• 2012

In this paper, a satellite array antenna operates at 12.2GHz~12.75GHz was designed and fabricated. The lowest height and high gain electrical beam tilt was obtained by applying backed slot and sub-reflector widening the distance between the patch and the GND. The simulation and measurement showed good agreements, the electrical beam tilt was $10^{\circ}$, the gain was 26.5dBi, the VSWR was less than 3:1 and the return loss was less than -15dB.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.414-414
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• 2007

In this study, Liquid Crystal (LC) alignment and tilt angle generation in Nematic Liquid Crystal (NLC) with negative dielectric anisotropy on the homeotropic PI surface with new ion beam exposure are reported. Also. high density of ion beam energy (DuoPIGatron type Ar ion gun) is used in this study. The tilt angle of NLC on the homeotropic Polyimide (PI) surface for all incident angles is measured about 38 degree and this has a stabilization trend. And the good LC alignment of NLC on the PI surface with ion beam exposure of $45^{\circ}$ incident angle was observed. Also the tilt angle of NLC on the homeotropic PI surface with ion beam exposure of $45^{\circ}$ had a tendency to decrease as ion beam energy density increase. The tilt angle could be controlled from verticality to horizontality. Also, the LC aligning capabilities of NLC on the homeotropic PI surface according to ion beam energy has the goodness in case of more than 1500 eV. Finally. the superior LC alignment thermal stability on the homeotropic PI surface with ion beam exposure can be achieved. For OCB(Optically Compensated Bend) mode driving, we can need pretilt angles control for fast response time. In this study, We success pretilt angles control. Consequently, this result can be applied for OCB mode.

• 정보저장시스템학회논문집
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• 제3권1호
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• pp.13-16
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• 2007

The purpose of this paper is real time tilt servo control of the holographic data storage system. Holographic data storage device is a next generation data storage device with high storage density, high transfer rate and short access time. This device is very sensitive to a disturbance due to the enormous storage density. As to the recording material changed disc type, the media continuously vibrates as the disc rotates. When disc rotates, deviation, eccentricity and unbalance disturbance are occurred. This disturbances cause disc tilt, finally reference beam does not illuminates to correct incidence angle. Therefore real time tilt servo control is essential. In this paper, the algorithm is proposed to make real time tilt detection in angle multiplexing of the holographic data storage system with an additional servo beam and the experiments are performed.

• 천문학회보
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• 제38권1호
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• pp.69.1-69.1
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• 2013

We are developing Adaptive Optics (AO) system for 1m telescope at Gwacheon National Science Museum Observatory. The beam spot of the Gwacheon 1m telescope. The tip-tilt correction system consists of a CMOS sensor, a tip-tilt mirror and a feed back loop. The beam spot location at the CMOS sensor indicates the tip-tilt components of the incoming light. The tip-tilt mirror is controlled by DAC output voltage calculated by proportional-integral-derivative (PID) controller. This system successfully corrects the tip-tilt motion of the spot.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3137-3143
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• 2009

본 논문에서는 한팔 나선 안테나(single arm spiral antenna)의 편파(polarization) 및 빔 틸트(beam tilt) 특성에 대하여 분석하였다. 한팔 나선 안테나는 나선 둘레 길이(spiral circumference length)가 한 파장 길이 이상 길어지면, 안테나의 최대방사 빔 방향이 안테나로부터 수직인 축빔(axial beam)으로부터 틸트되는 특성을 가지고 있다. 이때 나선 안테나의 급전위치(내부, 외부)에 따라 원형편파 (RHCP, LHCP)가 변화 하며, 안테나의 길이 변화에 따른 빔 틸트시 원형편파 특성에 따라 최대 방사 빔 방향이 서로 상이한 방향으로 틸트 됨을 검증하였다. 이러한 한팔 나선 안테나의 전기적인 특징을 이용하여, 단일 안테나로 이중 편파를 갖는 빔 포밍, 다이버시티, 또는 MIMO어플리케이션에 대한 적용 가능성을 확인하였다.

• 한국공작기계학회논문집
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• 제15권6호
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• pp.71-75
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• 2006

The application of focused ion beam (FIB) technology in micro/nano machining has become increasingly popular. Its usage in micro/nano machining has advantages over contemporary photolithography or other micro/nano machining technologies such as small feature resolution, the ability to process without masks and being accommodating for a variety of materials and geometries. The target of this paper is the analysis of FIB sputtering process according to tilt angle, dwell time and overlap for application of 3D micro and pattern fabrication and to find the effective beam scanning conditions using Taguchi method. Therefore we make the conclusions that tilt angle is dominant parameter for sputtering yield. Burr size is reduced as tilt angle is higher.