• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.82-86
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• 2001

In this Paper, we Propose synthetic aperture technique for twin-line may. Sin91e-line way is required long aperture size in order to achieve high SNR and angular resolution in shallow water Ultra low frequency signal from far-field has left-right ambiguity at sing1e-line array. To resolve these Problems, we'd like to adopt the synthetic aperture technique to twin-line array. The synthetic aperture method adopts coherent processing of sub-aperture signals at successive tine intervals in the beam domain. The proposed method shows low nile error and improved angular resolution. In simulation result, average sidelobe level is reduced about 7〔dB〕when the array Peformed 5-synthesis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.12
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• pp.1031-1043
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• 2015

This paper describes the pattern synthesis method of two kinds of conformal array antenna using the Enhanced Adaptive Genetic Algorithm (EAGA). One is the $1{\times}16$ conformal array antenna on a curved cylindrical metallic surface with quadratic function, and the other is the 18-element conformal arrary antenna on a metallic surface obtained by the rotation of a quadratic function curve around the axis. The active element pattern is utilized in the pattern synthesis. Especially for the case of the rotated-type conformal array antenna the transformed active element pattern obtained from the Euler's angle rotation of the active element pattern of the planar concentric array is utilized, which reduces the synthesis time a lot. To verify the validity of the proposed synthesis method the MATLAB results are compared with the MWS results. Furthermore, for the case of $1{\times}16$ conformal array antenna the measured results are compared with the MATLAB synthesized results.

• The Journal of the Acoustical Society of Korea
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• v.22 no.6
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• pp.482-488
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• 2003

Line may receiver contains an ambiguity on conjugate bearings, because of lacking aperture in transverse direction. To solve the left/right bearing ambiguity of line-array receiver we used line-array with cardioid beam. In addition, the synthetic aperture method adopts coherent processing of sub-aperture signals at successive time intervals in the beam domain. We presented performances about division of left/right bearing ambiguity according to array synthetic number of times in this paper.

• The Journal of the Acoustical Society of Korea
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• v.2 no.1
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• pp.59-66
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• 1983

본 논문은 랜념배열 안테나에서 위치함수의 확률분포함수가 정규 Gaussian 분포가 되도록 사다 리 계층법과 등면적 분포법이란 새로운 방법을 제시하였고 이를 선형과 판형 배열 안테나로 설치하여 그의 방사특성을 컴퓨터에 의해 계산하고 합성한 것이다 측정된 결과를 Monte-Carlo 법에 의한 랜념배 열 안테나와 균일 간격으로 배열된 안테나에 의한 측정결과와 비교한 결과 부로부레벨은 등면적 분포법 에 의한 배열안테나에서 가장 낮았으며 소자수가 많을수록 낮아졌다. 또한 빔폭은 확률밀도함수와 operture 길이에 의존함을 알 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.690-697
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• 2010

In this paper we propose an opposite-sign phase method to implement a nulling antenna using genetic algorithm. In the opposite-sign phase method the phase value of each antenna element in the linear phased array antenna is symmetrical to the center of the array and the sign of the phases of the neighboring elements is alternating. Compared to the conventional genetic algorithm our genetic algorithm shows the capability of synthesizing nulls faster and sharper.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.108-115
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• 2016

In this paper, the array synthesis horn antenna was designed and measured a radiation power after connecting magnetron. The proposed antenna was designed on the basis of the $4{\times}4$ array synthesis horn antenna characteristics. For suppressing a back-lobe, 2 step short-stub structures were attached to synthesis horn aperture upper and lower. The designed antenna has FBR(Front to Back Ratio) of 39.7 dB. HPBW(Half Power Beam Width) of the E-plane and the H-plane are $8.86^{\circ}$ and $7.35^{\circ}$ each in the measurement. For measuring a radiation power of array antenna that use a magnetron, the waveguide adaptor was designed and connected magnetron with horn antenna. Also, microstrip line coupler that replace a dielectric material with an air gap was designed for measuring a high power. As a result, average radiation output power of the $4{\times}4$ array synthesis horn antenna that connect a four magnetrons had a 0.063W.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.411-414
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• 2006

본 논문은 다양한 GPS 재밍대응 기술 중에서 안테나 기반의 CRPA(Controlled Reception Pattern Antenna) 시스템에 관한 소개 및 안테나의 널(null) 패턴 합성에 필요한 핵심 모듈인 디지털 I/Q 벡터모듈레이터(Vector Modulator)를 이용한 GPS용 $2{\times}2$ CRPA 패턴 제어방법에 관한 연구 내용이다. 일반적으로 시스템에서 미리 결정된 방향으로 만들어진 안테나 빔을 이용한 위상배열안테나(phased array antenna)와는 달리 CRPA 구조의 GPS 위성수신용 적응배열안테나(adaptive array antenna)는 각 안테나 소자(element)로부터 수신된 신호들을 실시간으로 해석하여, GPS 배열 안테나의 패턴 특성을 제어한다. 본 연구에서는 $2{\times}2$ 배열 정사각(square) 구조의 CRPA를 채택했으며, 재밍신호 방향으로 널(null) 패턴을 합성하기 위한 방법으로 PC에서 제어 가능한 DAC(Digital to Analog Converter)을 이용하여 I/Q 벡터모듈레이터로 인가되는 RF신호의 위상(phase) 및 진폭(amplitude)을 조절한다. 이때 원하는 널(null) 패턴이 합성되도록 네 개의 각 안테나 소자 쪽으로 8채널의 복소가중치(complex weight)를 인가한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.8
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• pp.758-764
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• 2015

This paper describes the pattern synthesis of array antenna which conforms to a metallic curved surface formed by the rotation of a quadratic function by using EAGA(Enhanced Adaptive Genetic Algorithm). Three rotated-type conformal surfaces are realized by changing the coefficient of the quadratic function and the pattern of each conformal array antenna is synthesized. In order to reduce the overall time of pattern synthesis, the transformed active element pattern obtained by the active element pattern of the 2-dimensional planar array using Euler angles rotation is utilized instead of the active element pattern of the 3-dimensional conformal array antenna itself. To verify validity of the proposed synthesis procedure, the synthesized patterns using EAGA are compared with those obtained by MWS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.1007-1019
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• 2006

In this paper, the synthesis method of multibeam radiation pattern with multi-directional beams and nulls is proposed. Genetic algorithm is applied for the optimization of amplitude and phase of the feeding signal into each element that is structured in planar array of single patch antenna with an arbitrary field distribution. To verify the validity of the proposed method, $2{\times}2$ planar array antenna is used for the measurement and the measured far field radiation pattern is compared with the simulation result. As a result, the synthesis of multibeam radiation pattern is implemented by the optimization of amplitude and phase of the feeding signal into each element of $8{\times}8$ planar array antenna system.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.299-304
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• 2018

An improved genetic algorithm was proposed for pattern synthesis of an adaptive beam forming system using phased array antennas. The proposed genetic algorithm is an algorithm that adds acquired characteristics procedure to solve local optimization using the diversity. The performance of the proposed genetic algorithm is verified through the problem of finding a suitable chromosome for a picture composed of binary. And it is confirmed that it is suitable for the adaptive beam forming system based on the performance problem of combining main beam and two pattern nulls.