• 전기학회논문지
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• 제59권11호
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• pp.1980-1985
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• 2010

This paper is about design of optimal structure of slot antenna array antenna with inner waveguide in accordance with the slot model, and fabrication of its prototype sample operating at the frequency of 24 GHz. Results of this work can be employed as a useful tool to develop and diversify slot antenna having superior performance and omni-directivity to that of current antenna. The implemented antenna demonstrates ultra-wideband performance for frequency ranges 24 GHz with the relatively high and flat antenna gain of 18.64dBi and low sidelobe levels. In addition, a $2{\times}8$ antenna array for phased-array systems and mm-wave sensor applications is also presented.

• 한국정보통신학회논문지
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• 제2권4호
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• pp.539-544
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• 1998

This paper presents the stabilization of a shipboard satellite antenna system. Hardware systems composing the pedestal, pedestal control unit and antenna control unit are designed and stabilization control law is obtained. A model on each control axis is derived and its parameters are estimated using a genetic algorithm, and the optimal state controller is designed based on the estimated model. An experimental result demonstrates the effectiveness of the proposed system.

• 전자공학회논문지A
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• 제33A권12호
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• pp.16-24
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• 1996

In this paper, the radiation pattern of the monopole antenna mounted on the portable phone is analyzed. The analyzed model consists of a rectangular conductor box and a monopole antenna. Even though the radiation pattern of the monopole has been well known, the monopole antenna mounted on the portable phone has not been fully studied. Because of the conductor box, portable phone acts as an unbalanced dipole antenna whoe radiation patterns deviate fro those of th econventional isolated monopole antenna. Therefore, the analysis of the radiation patterns of unbalanced dopole antenna is necessary. Using the moment method, its radiation patterns are analyzed and the numerical results are verified through the measurements. In addition, the radiation patterns depending on various length of the conductor box and the monopole antenna are also presented and the dimension of the portable phone which gives excellent radiation characteristics are derived from the analyzed results.

• 한국통신학회논문지
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• 제31권6A호
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• pp.563-574
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• 2006

본 논문에서는 OFDM(Orthogonal Frequency Division Multiplexing) 기반 다중 안테나 시스템의 링크레벨 성능 분석을 위하여 실제 전파 환경과 유사한 특성을 갖는 Ray-tracing 방식 채널의 하나인 SCM(Spatial Channel Model) 채널을 구현한다. 3GPP & 3GPP2 Spatial Channel AHG(Ad-hoc Group)에서 시스템레벨 성능 비교용으로 제안한 SCM 채널을 링크레벨 성능의 비교 분석을 위하여, 본 논문에서는 시스템레벨 채널에 대한 채널 계수 및 파라메터들을 링크레벨 성능 비교용으로 변환하여 구현한다. 모의실험을 통하여 구현한 SCM 채널의 특성을 검증하고, 이를 이용하여 기존의 OFDM 기반 MIMO (Multiple Input Multiple Output) 적용 시스템 및 스마트 안테나 적용 시스템에서의 실제적인 링크레벨 성능을 분석하고, 정확한 비교 검증을 위하여 SCM 채널과 동일한 파라메터를 적용한 I-METRA 채널 및 독립 채널 상황에서의 링크 레벨 성능을 함께 비교 분석한다. MIMO 및 스마트 안테나 적용 시스템에 대하여 여러 채널 환경에서 채널 상관도에 따른 링크레벨 성능을 분석함으로써, 채널 상관도의 영향에 따라 주어진 환경에 적합한 다중 안테나 시스템을 제안한다.

• 정보통신설비학회논문지
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• 제2권1호
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• pp.22-29
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• 2003

스트립라인/이중슬롯라인 변환구조에 대한 등가회로모델과 넛치 안테나를 해석하기 위한 segmented method를 제시하였다. 변환구조에 대한 등가회로 모델을 구축하기 위하여 이중슬롯라인에 대한 특성 임피던스, 분산특성과 단락 임피던스에 대한 계산을 통하며 해석적인 해로 근사화하였다. Segmented method는 이중슬롯라인 급전 넛치 안테나의 최적 설계를 구현하기 용이하게 해준다. 설계 예제로 넛치 안테나를 4차 Marchand 밸룬과 이중슬롯라인 급전 넛치 안테나로 분할하여 해석하였으며, 제안된 등가회로모델과 비교하여 타당성을 검증하였다.

• 한국정보통신학회논문지
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• 제3권4호
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• pp.755-764
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.33-51
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, Maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• International journal of advanced smart convergence
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• 제2권1호
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• pp.21-23
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• 2013

The antenna pattern in this case has a main beam pointed in the desired signal direction, and has a null in the direction of the interference.The conventional antenna pattern concepts of beam width, side lobes, and main beams are not used, as the antenna weights are designed to achieve a set performance criterion such as maximization of the output SNR.A new direction of arrival estimation method using effects of model errors and sensitivity analysis is proposed. Two subspaces are used to form a signal space whose phase shift between the reference signal and its effects of model error signal. Through simulation, the performance showed that the proposed method leads to increased resolution and improved accuracy of DOA estimation relative to those achieved with existing method. Since a desired signal is obtained after interference rejection through correction effects of model error, the effect of channel interference on the estimation is significantly reduced.

• ETRI Journal
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• 제31권3호
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• pp.321-323
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• 2009

A wideband beamforming algorithm for estimating the azimuth angle, elevation angle, velocity, and range using a planar phased radar array with antenna switching is proposed. It uses the time-variant steering vector model. Simulation results illustrating the performance of the proposed beamformer are presented.

• ETRI Journal
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• 제40권2호
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• pp.188-196
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• 2018

This paper presents a pulse radar system to detect drones based on a target fluctuation model, specifically the Swerling target model. Because drones are small atypical objects and are mainly composed of non-conducting materials, their radar cross-section value is low and fluctuating. Therefore, determining the target fluctuation model and applying a proper integration method are important. The proposed system is herein experimentally verified and the results are discussed. A prototype design of the pulse radar system is based on radar equations. It adopts three different pulse modes and a coherent pulse integration to ensure a high signal-to-noise ratio. Outdoor measurements are performed with a prototype radar system to detect Doppler frequencies from both the drone frame and blades. The results indicate that the drone frame and blades are detected within an instrumental maximum range. Additionally, the results show that the drone's frame and blades are close to the Swerling 3 and 4 target models, respectively. By the analysis of the Swerling target models, proper integration methods for detecting drones are verified and can thus contribute to increasing in detectability.