• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1282-1290
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• 2000

The LHCP circularly polarized antenna operating at the satellite broadcast receiving band is developed by employing the sequential-rotation technique in which each truncated-corner patch square element is arranged in the triangular lattice type. Antenna designed with sequentially rotated technique of triangular lattice type has the effect of improved axial-ratio bandwidth, cross-polarization etc., and the degradation of radiation pattern can be reduced significantly by minimizing the radiation loss of feeding line structure. Characteristics of antenna designed is satisfied with specifications of array antenna for DBS that is -27 dB of side lobe level and -20 dB of cross-polarized level at $\Phi$=45$^{\circ}$ plane.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.614-623
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• 2011

We propose a real-time tracking algorithm for an augmented reality (AR) system for TV broadcasting. The tracking is initialized by detecting the object with the SURF algorithm. A multi-scale approach is used for the stable real-time camera tracking. Normalized cross correlation (NCC) is used to find the patch correspondences, to cope with the unknown and changing lighting condition. Since a zooming camera is used, the focal length should be estimated online. Experimental results show that the focal length of the camera is properly estimated with the proposed online calibration procedure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.894-900
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• 2004

There are many types of circularly polarized(CP) microstrip antenna elements, which are used as a good unit radiator. Since an advantage of CP antenna is no strict alignment requirements between Rx and Tx system, the printed antennas with circular polarization are very often used in numerous satellite and mobile radio systems. In order to realize the broad bandwidth of 3 dB axial ratio and impedance of CP microstrip antenna, complex feed structure and tri-plate patch element have been researched. This paper describes a design of wideband microstrip cross slot array antennas with circular polarization. The proposed antenna is composed of an open-ended microstrip feed line as a feeder and a cross slot as a radiator for circular polarization. To realize the wide bandwidth, tri-plate structure are considered and cross slot is electromagnetically coupled with feed line. Optimum parameters of 1-element cross slot antenna are analyzed and designed by method of moments. These parameters are also applied to may antennas design considered the mutual coupling between radiating elements. Right hand circular polarization(RHCP) and left hand circular polarization(LHCP) of the proposed antenna are easily controlled by asymmetrical cross slot structure and slot position. In 1-element and 15-element cross slot array antenna, the good axial ratio of 1 dB below and the broad bandwidth characteristics of antenna are obtained.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.488-491
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• 2009

본 논문에서는 응력함수와 Kantorovich method를 이용하여 기저판(substrate)에 인장과 굽힘이 작용할 때 복합재 패치의 3차원 응력을 해석하였다. 면내 방향과 면외 방향의 두 응력함수에 가상 공액일의 법칙(Complementary virtual work principle)을 적용하였으며 복합재 패치의 자유 경계조건과 바닥의 기저판으로부터 전달되는 전단 수직 응력 조건을 부여하였다. 이를 통해서 패치 구조물의 지배방정식을 연립 미분 방정식 형태의 고유치 문제로 변환하여 응력함수를 구하였다. 위 방법의 타당성과 효용성을 검증하기 위한 수치 예제로 cross-ply, angle-ply, quasi-isotropic의 패치 적층 배열을 고려하였으며, 층간 응력함수 값이 자유 경계에서 최고치를 나타내고 패치 중심부로 갈수록 급격히 감소하는 모습을 확인하였다. 제안된 기법은 기저판에 인장하중이 작용하는 경우뿐만 아니라 굽힘 하중이 작용하는 경우에도 정확한 예측이 가능하여, 패치 구조물의 층간 응력을 포함한 3차원 응력을 해석하는데 있어서 효율적인 해석 도구로서 사용할 수 있을 것이라 사료된다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1656-1657
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• 2011

본 논문에서는 RF 프로브를 이용하여 평면 구조물의 RCS(Radar Cross Section)를 감쇄시키기 위한 방법을 제안하였다. 우선적으로, EM 시뮬레이터를 이용하여 제안한 방법에 대한 가능성을 증명한 후 실험을 수행하였다. x-band 에서 $10{\lambda}$의 알루미늄판 위에 FR4 기판을 이용하여 patch 형태로 제작된 RF 프로브를 설치하였으며, 그 후 알루미늄 판으로 입사되는 외부 전자파를 상쇄시키기 위하여 RF 프로브로부터 전자파를 방사하였다. 로테이터를 사용하여 알루미늄판을 phi 방향으로 회전하여 임의의 각도로 입사하는 평면파에 대해서도 반사파의 크기를 측정하였다. RF 프로브로부터 방사된 전자파의 세기와 위상은 신호 발생기와 위상 천이기를 이용하여 조절되었다. 결과적으로 무반향실에서의 실험을 통해, 알루미늄판에 의해 반사되는 전자파를 측정하여 외부 전자파의 상쇄 정도를 확인하였다.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.160-168
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• 1999

This paper describes one method of reverse engineering that machines a free form shape without descriptive model. A portable five-axes 3D CMM was used to digitize point data from physical model. After approximation by rational B-spline curve from digitized point data of a geometric shape, a surface was constructed by the skinning method of the cross-sectional design technique. Since a surface patch was segmented by fifteen part, surface merging was also implemented to assure the surface boundary continuity. Finally, composite surface was transferred to commercial CAD/CAM system through IFES translation in order to machine the modeled geometric shape.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.205-212
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• 2003

Many people are exposed to accidents by vehicles or sports. The most frequent injuries by these accidents is concerned with a knee joint. The three-dimensional surface model of a knee is needed for dynamic analysis of knee motion and knee reconstruction. three-dimensional motion data of a knee joint were obtained using X-ray and precise magnetic sensors. The surface data of a femur and a tibia were obtained using cross-sectional pictures by CT. The three-dimensional surface models of a femur and a tibia were made by the method of optimal triangular patch. Using obtained motion data, we simulated the motion of three-dimensional knee joint model.

• Journal of Chest Surgery
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• v.29 no.2
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• pp.213-218
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• 1996

Total anomalous pulmonary venous return (TAPVR) is very rare congenital heart disease. 25-year old male was admitted our hospital with dyspnea, headache and syncope as chief complaint. He was confirmed as mixed type TAPVR by echocardiography and cardiac catheterization. In this case, mixed type TAPVR was consisted with supracardiac type connection of left pulmonary vein and cardiac type of right pulmonary vein. Supracardiac type of left pulmonary common channel was anastomosed to the left auricular appendage during total cardiopulmonary bypass with fibrillating heart. Cardiac type of right pulmonary vein was operated during moderate hypothermia and aortic cross clamping. Coronary sinus septum was incised into ASD and closed with Gore-Tex patch so that right pulmonary blood flow directed to the left atrium. The patient's post-operative course was uneventful.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.1001-1004
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• 2000

RFID system is applied to identify, locate and track people, cars, animals. In RFID system, the passive transponder without battery has some benefits than active transponder, such as no restriction in battery exchange and in battery’s life. But it needs auxiliary RF-DC conversion circuit. RF-DC conversion circuit originated from Wireless Power Transmission (WPT). In this paper, RF-DC conversion circuit consists of a microstrip patch antenna and impedance matching circuit, Cock-croft Walton circuit. And RF-DC conversion circuits have two kinds of T-type and Cross-type impedance matching circuits.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.