• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.273-277
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• 2002

본 논문에서는 원형편파를 송신하고 수직 및 수평편파를 합성하는 방식의 원형편파 다이버시티시스템을 설계 및 제작하였나. 중심주과수 2.4GHz의 수직 및 수평편파안테나 그리고 90도 Hybrid Combiner를 설계 제작하여 원형편파 다이버시티시스템의 송신계를 구성하였고, 수직 및 수평편파 안테나와 편파 다이버시티 합성기를 설계 제작하여 원형편파 다이버시티시스템의 수신계를 구성하였다. 선계에 사용된 프로그램은 Ensemble 5.0이고 제작된 안테나, 위상기 및 합성기는 Network Analyzer(8753ES)를 이용하여 측정했으며 시뮬레이션 결과와 측정결과가 상당히 일치함을 확인했다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.398-401
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• 2002

본 논문은 최근 사용이 증가하고 있는 1㎓ 이상 장해파의 허용 기준안을 정하기 위한 측정에 이용되는 피시험체의 최적 회전 스텝 크기를 결정하고 방사 패턴의 측정 및 결과를 나타내었으며 기가헤르츠 대역의 CISPR 허용기준치와 비교하였다. 실제 피시험체를 측정한 결과, 가장 좁은 3㏈ 빔폭은 수평편파에서 약 18도, 수직편파에 대해 약 20도 정도이다. 최대 방사 방향에서 3㏈ 빔폭의 경우 수평편파에서는 60도이며 수직 편파에 대해서는 50도를 보였고, 적절한 스텝 크기는 40개였다. 또한 CISPR에서 제안한 허용기준치에 측정값이 만족하는 것을 알 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.302-311
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• 1999

In this paper, in order to suggest an optimal polarization diversity composition method in indoor radio wave propagation environments, the variation of the cross polarization discrimination(XPD) was theoretically analyzed by a computer simulation and compared to the actual measured data. From the results, it can be seen that the cross polarization discrimination of the case, a circularly polarized antenna was used at the transmitting end as well as the vertical and horizontal polarized antenna branches were used at receiving end (CV-CH), is lower than that of the case, horizontal polarized antenna at the transmitting end as well as the horizontal and vertical polarized antenna branches at the receiving end(HH-HV), and that of the case, vertical polarized antenna at the transmitting end as well as the vertical and horizontal polarized antenna branches at the receiving end(VV-VH). In this paper, to get more effective CV-CH polarization diversity composition, the amount of cross polarization discrimination values at the signals received by horizontal polarized antenna is compensated and the polarization diversity effect through the cumulative probability distribution is estimated. From the evaluation results, it was found that the polarization diversity effect was better at the compensated case than at the uncompensated case. On the other hand, it can be known that the polarization diversity effect is getting better as the cross polarization discrimination values are getting lower, and also be known that the effect can be improved if a transmitting antenna is composed of the ellipse polarized antenna by adjusting the axial ratio of the circularly polarized antenna and, a receiving antenna is made up of the vertical and horizontal polarized antenna branches.

• 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.9 no.2
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• pp.265-277
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• 1998

In this paper, to investigate the possibility of fading reduction effect and high transmission rate in indoor multipath propagation environment, we measured and analyzed broadband signal conducting by frequency sweeping method in LOS(Line-of-Sight) environment. In measuring, we used vertically polarized, horizonatally polarized and circularly polarized and circularly polarized antenna to compare the fading reduction effect and the characteristic of bandwidth amplitude fluctuation between each broadband signals. As a result, it can be seen that the circularly polarized antenna can reduce the amplitude deviation of the broadband signal because it can remove the odd-times reflected wave in LOS environment. And also, It was found that the best effective diversity reception method is to use polarization branches, which install a circularly polarized antenna at the transmitting end and compose the vertical and horizontal antenna at the receiving end.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.746-755
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• 2014

In this paper, we propose the structure of a dual polarized system for a wireless communication. The proposed dual polarized antenna is formed by one vertical antenna and two horizontal antennas that are orthogonal to each other. Vertical and horizontal polarized antennas transmit different signals, but two orthogonal horizontal polarized antennas transmit the same data signals. So, the signals of the proposed dual polarized system construct two dual-polarization planes. And, only one dual-polarization plane with a large signal power is selected at the side of a receiver. The simulation results show that the proposed dual polarized system could obtain a higher capacity compared to an ordinary $2{\times}2$ MIMO (Multi-input Multi-output) system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.133-138
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• 2003

In this paper, we analyzed a two-branch polarization diversity at a mobile station in NLOS environment when a base station transmits a circularly polarized wave. In order to calculate the correlation coefficient considering the XPD(cross polarization discrimination) between the received signals for the two diversity branches, a simple theoretical model of circular polarization diversity is adopted. From the analysis results, it can be seen that the XPD of circularly polarized wave is less than vertically polarized wave about 6~7 dB in measurement results. And also, it is clearly seen that the correlation coefficient of circular polarization diversity evaluated by the XPD is less than that of vertical polarization diversity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.872-878
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• 2003

In this paper, we developed a simulator which can generate the polarization waves for the indoor wireless communications based on three dimensional ray tracing technique and verified the simulation results comparing with the measured data in indoor wireless propagation environments. Using the developed simulator, we analyzed the channel characteristic and polarization diversity reception characteristic for the vertical, horizontal and circularly polarized waves. From the analysis results, in the case of using circularly polarized wave it can be clearly seen that the multipath fading is markedly reduced compared to the vertical and horizontal polarized waves due to the reception characteristic of removing the odd time reflected waves.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.4
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• pp.473-478
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• 2011

The extent of a rectangular conducting plane for measuring electromagnetic interference is discussed. Mutual coupling between the transmit and receive antennas is negligible, the effects of the ground plane on the normalized site attenuation(NSA) are considered by applying GTD(Geometric theory of diffraction). The calculation was done for the case that measuring distance(d) was 3 m for both horizontal and vertical polarizations. As the result, the size of the rectangular ground plane almost never affects upon NSA for horizontal polarization, but for vertical case, when both width and length of the rectangular plane are several times as long as distance, the effects of the edges are reduced under 1 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.261-268
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• 2016

In this paper, dual-polarized monopulse cassegrain antenna for W-band millimeter-wave seeker was proposed and the performances were verified by the measured results of the fabricated antenna. Dual-polarized monopulse Cassegrain antenna consists of main/subreflector, dual-polarized feed horn and monopulse comparator. The proposed feed horn has $2{\times}2$ array square waveguide feeding structure to make monopulse signals and it was designed using 90 degree rotational symmetric structure to receive dual-polarized signals. At the sum and difference channel, the measured vertical and horizontal polarization radiation pattern were similar. Measurement gains are 35.1 dBi for v-pol. and 35.6 dBi for h-pol. at the center frequency with 0.5dBi difference between each polarization and the side lobe level is below -21.6 dB.