• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.130-133
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• 2010

본 논문에서는 X-band 절전센서용 마이크로스트립 구형패치 배열 안테나의 설계 방법을 제안 하고자 한다. 제안된 배열 안테나는 송 수신 안테나가 각각 1x2배열로 구성 되었다. 안테나는 CST MWS를 사용하여 시뮬레이션 하였고 FR-4 기판(h=1.0mm, ${\varepsilon}_r$=4.4)을 사용하여 제작하였다. 시뮬레이션 결과는 대역폭이 4%(VSWR${\leq}$2), 이득은 6.3dBi, 빔폭은 약 $60^{\circ}$(El)/$15^{\circ}$(Az)로 예측되었다. 안테나는 시뮬레이션 결과를 바탕으로 제작 되었고 절전센서용 RF 송수신기 회로 뒷면에 설치되어 무반사실에서 방사 특성을 측정하였다. 측정된 결과는 대역폭이 7%(VSWR${\leq}$2), 이득은 4.8dBi, 빔폭은 약 $55^{\circ}$(El)/$15^{\circ}$(Az)로 시뮬레이션 결과와 매우 유사한 결과를 얻었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1142-1148
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• 1999

In this paper, the characteristics of frequency dependent dispersion are analyzed for the phase shifters in Ku-band phased array antenna system using full-wave method, SDA(Spectral Domain Approach).The design technique of asymmetric coupled-line phase shifter with dielectric overlay is proposed. The compared results of phase responses are shown with conventional symmetric coupled-line Schiffman phase shifter. The experimental results verify the improvement of broadband characteristics by the increasing bandwidths and the decreasing phase deviations.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.200-205
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• 2011

In multipath fading channel, diversity is essential to mitigate the impairments. In this paper, we have proposed the angle diversity scheme called ATTD(Angle Time Transmit Diversity) instead of Alamouti's STTD(Space Time Transmit Diversity) and have analyzed the performance of the proposed scheme when signal powers caused by the transmission to different angles are different. Based on it, we have measured the wireless vector-channel in the urban area, which has lots of high-story buildings, using the data collected from the 8 by 4 smart array antenna system that we made. According to the measured data, the received signals from different angles have different signal powers. Our performance analysis results show that the proposed scheme has better performance than the space diversity scheme when the received path signal power is at least -7dB compare to the strongest path signal power.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.114-120
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• 2003

Blind channel estimation of communication channels is a problem of important current theoretical concerns. Recently proposed solutions for this problem exploit the diversity induced by antenna array or time oversampling, leading to the so-called, second order statistics techniques. This paper proposes the blind adaptive channel estimation using multichannel linear prediction method. Computer simulations are presented to compare the proposed algorithm with the existing ones.

• Journal of information and communication convergence engineering
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• v.3 no.3
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• pp.115-118
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• 2005

In this study, the proposed algorithm is a correlativity signal in a mobile wireless channel that has estimated the direction of arrival. The proposed algorithm applied the space average method in a MUSIC algorithm. The diagonal matrix of the space average method was changed to inverse the matrix and to obtain a new signal correlation matrix. The existing algorithm was analyzed and compared by applying a proposed signal correlation matrix to estimate the direction of arrival in a MUSIC algorithm. The experiment resulted in a proposed algorithm with a min-norm method resolution at more than $5^{\circ}$. It improved more than $2^{\circ}$ in a MUSIC algorithm.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.3
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• pp.98-104
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• 2002

An airborne-based Direction-Finding System is developed for the application of ELINT and ES(Electronic Support). The system takes the phase-comparison technology, and has the configuration of multi-based antenna array for the solution of ambiguity due to the increased Direction-Finding resolution. This thesis describes the design of optimized distances among antennas, the electrical characteristics, the method of compensation, the direction-finding accuracy, and et. al. under the condition of the airborne-based environment.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.3-5
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• 2002

최근 기계적으로 빔을 움직일 수 있는 마이크로 스트립 패치 배열 안테나가 MEMS 기술을 이용해서 제작되고 시험되었다. 본 논문에서는, 제작된 안테나의 적용 예로써 위상변위기를 사용하지 않는 새로운 어레이 안테나의 방사패턴 합성방법을 제안하고, 제안된 방법을 원하는 빔 형상합성에 적용하였다. 방사패턴 형상의 최적화에는 Restricted Competition Selection(RCS)를 이용한 유전 알고리즘을 이용하였다. 또한 이러한 방식의 접근은 EMC 표준에 대처하기 위한 배열 안테나의 설계 시에도 적용이 가능하며, 제안된 방법을 이용하여 특정한 빔 형상들에 대한 합성이 가능하다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.459-464
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• 2001

We propose a transmit beamforming algerian for array antenna in FDD (Frequency Division Duplex) environments. The proposed method estimates the directions and spectra of the users, and constructs the spatial covariance matrix of the interferences at the downlink frequency. The weights are computed by that covariance matrix and desired user's direction vector Simulations are performed under Rayleigh fading environments. The proposed method don't need the data feedback, has the enhanced performance in BER (Bit Error Rate).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3C
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• pp.279-285
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• 2006

In this study, a new signal model suitable for UWB indoor environments with random angle spread is proposed to estimate the angle-of-arrivals(AOAs) of UWB cluster signals in an UWB wireless communication. A subspace based estimation technique adopted for this model is investigated and the estimates of the AOA and distribution parameter on the received UWB cluster signals are obtained. The proposed model and estimation technique are verified using computer simulations, and the performance of the estimation error is analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.18-26
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• 2006

In this paper, we propose new beamforming algorithm which overcomes signal cancellation effect even high cross correlation existing between target and interfering signal. Using the proposed method, we show that direction of arrival (DOA) of interfering signal can be estimated using correlation matrix and the cross-correlation can be eliminated in the correlation matrix of input signal. The proposed method gives high performance enhancement compared with the spatial averaging method in our computer simulation results.