• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.49-52
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• 2001

A virtual antenna system is presented to increase the channel capacity of a smart antenna in cdma2000. Although a smart antenna system can increase channel capacity by forming a beam to a desired user direction, an increase of channel capacity is limited by the number of antenna elements. A virtual antenna is proposed to improve the channel capacity by increasing the degree of freedom. The results show that the proposed system has a larger channel capacity than a conventional smart antenna system for the same number of antenna elements.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.525-528
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• 2005

The tracking antenna system must be always pointed to target moving vehicle. Especially, for an antenna mounted on a movable vehicle, it needs the stabilized antenna system. In this paper, two types of fuzzy controller were derived and applied to a data link antenna system and the altitude control of unmanned helicopter, respectively. A simplified Fuzzy-PID controller was designed for 2-axes antenna stabilization and tracking system and the performance was verified by simulations and experiments. Computer simulations were performed by Matlab and SIMULINK. A 2-Axes antenna (SeaTel 1898 model) was selected as test platform of this research. The antenna was modified by using two Blushless Direct Current motors and an embedded DSP controller. To verify the performance of designed antenna servo control system, the performance of the conventional PID controller and that of the Fuzzy-PID controller, designed by the same PID control gains, were compared.

• 대한전자공학회논문지TC
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• 제47권1호
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• pp.43-52
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• 2010

본 논문에서는 스마트 안테나 기능을 지원하는 mobile-WiMAX 시스템을 구현하였고, 기존의 단일 안테나 m-WiMAX 시스템과 성능을 비교하는 실험을 하였다 스마트 안테나 기능을 지원하는 m-WiMAX 시스템을 구현하기 위해 여러 고려 사항이 있다. 그 중에 스마트 안테나 방식의 특성상 심볼 동기 획득, 빔형성, 캘리브래이션을 특히 잘 구현 해야만 원하는 성능의 스마트 안테나 기지국을 구현할 수 있다. 본 논문에서는 위의 3가지를 구현하였고 3가지가 제대로 구현되었을 때 스마트 안테나 시스템이 단일 안테나 시스템보다 성능이 우수하다는 것을 검증하였다. 4 배열 안테나의 환경에서 스마트 안테나 시스템은 데이터 산출량 관점에서 단일안테나 시스템보다 5.5dB의 성능향상을 실험을 통해 확인할 수 있었고 이는 이론적인 수치인 6dB와 거의 일치하는 결과 이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.413-416
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• 2004

The tracking antenna system must be always pointed to a satellite for data link among moving vehicles. Especially, for an antenna mounted on a moving vehicle, it needs the stabilized the antenna system. So, software and hardware, signal processing of motion detection sensors, real-time processing of vehicle dynamics, trajectory estimation of satellite, antenna servo mechanism, and tracking algorithm, are unified in the antenna system. The purpose of this paper is to design the embedded tracking antenna control system for satellite communication. The embedded OS(Operating System) based stabilization and tracking algorithm was implemented. The performance of the designed embedded control system was verified by the real satellite communication test.

• 정보통신설비학회논문지
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• 제5권1호
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• pp.43-59
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• 2006

A compact and broadband $4\times1$ array antenna was developed for 3G smart antenna system testbed. The $4\times1$ uniform linear away antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% $(VSWR\leq1.5)$, 21.78% $(VSWR\leq2)$ with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• 정보통신설비학회논문지
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• 제7권1호
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• pp.41-58
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• 2007

A compact and broadband $4{\times}1$ array antenna was developed for 3G smart antenna system testbed. The $4{\times}1$ uniform linear array antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% ($VSWR{\leq}1.5$), 21.78% ($VSWR{\leq}2$) with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.546-555
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• 2009

안테나의 다양한 응용과 더불어 안테나 제작에 필요한 안테나 특성 측정에 관한 관심이 증대됨으로 안테나 측정 시스템의 정밀도가 더욱 필요하게 되었다. 안테나 측정시 사용자의 수동작을 기반으로 하는 기존의 시스템은 사용자의 위치 보정 작업에 기반을 함으로 오차를 유발한다. 따라서 안테나 특성의 자동 측정 시스템 도입이 필요하다. 본 논문에서는 안테나 자동 측정 시스템을 위한 안테나 추출 알고리즘을 제안한다. 제안 알고리즘은 안테나 측정 시스템에서 안테나에 대한 영상 정보 획득하고 획득된 영상 정보로부터 안테나 객체를 추출하여 안테나의 기울어짐과 위치 파라메터를 추출한다. 추출된 파라메터는 위치 및 기울어짐 각도를 보정하는데 사용되며 안테나의 자동 측정을 위해 사용된다. 제안한 알고리즘은 다양한 안테나 중 패치 안테나를 중심으로 적용되며 패치 안테나 객체가 효율적으로 추출되고 왜곡 보정을 위한 각도도 측정됨을 보여준다.

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.79-85
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• 2010

In this paper, a directive antenna design with a combination of electric-magnetic radiators for an radio frequency identification(RFID) system is presented. To generate a directive antenna radiation pattern, a structure combining a dipole and loop antenna is presented. A reader antenna and tag antenna are proposed for the RFID system. For the reader antenna, the frequency bandwidth defined by $S_{11}$<-10 dB is approximately from 820~990 MHz. The forward and backward gain differences are 1.5~2 dBi. For the tag antenna, the frequency bandwidth is approximately from 860~920 MHz with a maximum gain of 3.58 dBi at 910 MHz. In both cases, directive radiation characteristics are observed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.101-104
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• 1996

A new detecting system for moving objects of coastal region has been designed by directional antenna and driving circuits. The designed system has been investigated by CAD for linear and planar antenna arrays of various radiating elements for antenna simulations and by P-spice of device simulations. For detecting the displacement of moving objects, we constructed four wideband dipole antenna, diode switching circuit, mixer, filter and amplifier. The results of antenna receiver were shown a possibility of distance measuring system through phase difference of radiation patterns in antenna simulation

• 대한기계학회논문집A
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• 제29권5호
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• pp.743-753
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• 2005

The model of azimuth driving servo system with a flexible antenna in a prototype gimbal has been derived in this work. The validity of the model is verified by comparing the result of the model with that of experiment. It is found that one should consider an antenna as a flexible body in case of modeling the dynamics of the gimbal with an antenna. It is also known that the effect of reducing backlash magnitude for extending the bandwidth in the system with a flexible antenna is smaller than the system with a stiff antenna. It is thought that the model-based design optimization of the gimbal with an antenna will be possible by virtue of the derived model, when a weight reduction and a bandwidth extension are required.