• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.157-161
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• 2000

본 논문은 2린 대역의 마이크로 셀 환경에서 원편파 특성을 분석하기 위하여 편파의 특성을 이론적 해석과 실제 측정 데이터를 비교 검토하였다. 가시거리에서는 원편파가 기수회 반사파 수신을 억제하기 때문에 다중경로 페이딩에 대한 경감 효과가 있다는 것은 널리 알려져 있다. 본 연구팀은 "E"자형 건물의 회절 음영 지역에서도 원편파의 편파 특성이 잘 유지되는지를 측정 분석하였다. 이를 위해 정선회 원편파(C), 역선회 원편파(X), 수직편파(V), 수평편파(H) 안테나를 사용하여 각각의 송수신 편파간 조합에 대하여 거리에 따른 전계강도를 이동 측정하였다. 전파 모델은 "E"자형 건물의 회절지역 모델에서 2개의 경로를 선택하여 각각에 대한 전파의 편파 특성을 분석하였다.대한 전파의 편파 특성을 분석하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.461-466
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• 2004

In this paper, the novel patch antenna for polarization diversity using switching element is presented. The proposed antenna consists of the square patch with a pair of truncated corners and a microstrip-feed line with power divider. A switching microstrip-line feed works at schottky diode ON / OFF that is placed at $\lambda$/4 point from branch-off point of power divider. Polarization diversity has two types(LHCP. RHCP) as switching the schottky diodes. The measured 3 ㏈ axial ratio bandwidth for switching operation is about 2 %.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1623-1625
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• 2003

마이크로과 방전 무전극 황전등은 마그네트온에서 발생된 마이크로파로 2-원자 황을 여기하여 방출되는 빛을 조명에 사용하는 차세대 조명기구이다. 1990년대 초반에 미국의 Fusion Lighting Inc에 의해 최초로 소개된 무전극 황전등은 방전구 회전에 의한 방전을 하였다. 기존의 방전기술은 선형편파를 이용, 필드가 중앙에 모이므로 램프를 회전시켜 방전을 유지하였다. 그에 따라 시스템 구성이 복잡해지고 램프회전 속도에 따라 방전에 영향을 주었다. 본 논문에서는 원편파를 이용하여 램프 회전에 따른 문제점을 해결하고, 원편파에 의해 발생된 회전 플라즈마 방전현상을 실험적으로 보인다. 또한 원편파 방전에 의판 분광분포 및 휘도 분석등 방전 현상을 관찰했다. 아울러 연색성이 80이상, 색온도 4900k ${\sim}$ 6827k 범위를 보였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.49-56
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• 2004

An OFDM system using cross-handed circular Polarization(XCP-OFDM) is newly proposed in his paper. The proposed XCP-OFDM system divides the subchannels into a right-handed circular polarization(RHP channel and a left-handed circular polarization(LHCP) channel that alternate each other. Therefore, the overlaps between subcarriers in XCP-OFDM system can be reduced to a great extend compared to the conventional OFDM system. By this reason, it can improve the orthogonality and reduce the inter-channel interference due to frequency offset. In this paper, it can be seen that the proposed XCP-OFDM system shows robust against frequency offset.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.330-337
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• 1998

In this paper, we fabricated a pair of circulaly polarized conical horn antennas for evaluating the scattering characteristics of a hemispherical reflector and of propagation characteristics in in-building environments, which is required for constructing a new wireless in-building communication system of microwave band consisted of a hemispherical reflector installed on the ceiling. The measurements show the fairly good features such that cross-polarization discremination more than 27 dB and axial-ratio less than 1.25 dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.161-164
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• 2001

본 논문에서는 주어진 주파수대역에서 우수한 원편파 특성을 가지고 광대역에서 저반사 손실을 가지는 이종대역 안테나 피드용 원형도파관 유전체 편파기의 설계기법을 제시하였다. 양호한 편파특성을 위한 유전체판 두께와 원형 도판관 직경의 결정방법을 제시하였다. 또한 이종 대역 안테나 피드용으로 광대역에서 저반사 손실을 가지기 위한 유전체 형상 설계기법을 제시하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.3
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• pp.254-262
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• 1996

In this paper, we present a polarizer that consists of three step rotary detents which can selectively convert linear polarzation into circular polarization and vice versa. For the design of the polarizer, the transmission line theory is applied to design the wa- veguide mode transducer for the modes to be smothly converted in waveguides, and a dielectric plate is inserted in circular waveguide for the conversion of a polarized wave with the angle of an inserted dielectric plate. Also, we simulated to obtain the optimum values of the transmission and the reflection coefficient characteristics at input and output port, and proved the propriety of the theory from the knowledge of measuring the constructed polarizer with the designed data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.8
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• pp.730-739
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• 2015

In this paper, a wideband circular polarizer operating in the frequency range of 6~18 GHz is designed and fabricated using a multilayer structure with meanderlines. A T matrix expression for the unit structure, which consists of meanderline, dielectric substrate and spacer, was derived using the boundary value solution. A proposed meanderline structure was modeled as an array of unit meanderline cell in order to apply the waveguide model with PEC and PMC boundary conditions. The calculation procedures to obtain an equivalent susceptance of the unit meanderline cell using HFSS was also suggested. Using a hybrid method, which combines the T matrix with the HFSS results, and cut-and-try method, a wideband circular polarizer with low insertion loss and good AR performance was designed. The fabricated polarizer has the return loss less than -10 dB within 92 % bandwidth, the average insertion loss less than -0.24 dB, and the average AR below 2.6 dB for full 3:1 bandwidth.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.119-123
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• 2000

This paper described a design for microstrip antenna with EMC cross dipole for circular polarization. To realize the wide bandwidth and circular polarization, the elertromagnetic-coupled cross dipole are used. The calculated axial ratio is about 0.1 dB in the main bean direction at 12 GHz and the circular polarization is realized.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.757-765
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• 1999

In this paper, L-Type aperture coupled circular polarization patch antenna for mobile communication(IMT-2000, 1.9375 GHz), which is capable of being mounted in mobile unit, was designed and fabricated. This antenna is expanded to the $2\times2$ circular polarization array antenna for satellite mobile communications which are using the L-band frequency. The results are as followings : Returnloss 18.56 dB, beamwidth $60^{\circ}$, gain 7 dBd, axial ratio 0.9 dB in the case of single element and returnloss 28.43 dB, beamwidth $38^{\circ}$, gain 9.8dBd, axial ratio 1.5 dB in the case of $2\times2$ array, respectively.