• Title, Summary, Keyword: 위상배열

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A Study on Efficient Configuration of Array for Phased Aray Antenna with Hybrid Phased Shifting Device (복합 위상천이기 구성을 갖는 위상배열안테나의 효율적인 배열구성에 관한 연구)

  • Jung, Jin-Woo;Park, Sung-Il;An, Hyung-Soon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.6
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    • pp.1199-1206
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    • 2018
  • The hybrid phase shifting device is consist of general phase shifter in sub-array and the true time delay inter sub-array. This configuration for phased shifting can efficiently improve the beam squint according to frequencies. However, when an appropriate array configuration is not selected, a gain variation of main lobe for a phased array antenna is occurred. In order to solve these problems, a simplified formula for constructing efficient array based on the system design requirements, such as the fractional bandwidth, the maximum beam steering angle, and limit criterion of the gain variation, was presented.

Recent Technology on Active Phased Array Atennas using Coupled Oscillators (결합발진기를 이용한 능동위상배열 안테나 기술 최근 동향)

  • Myeong, No-Hun
    • Information and Communications Magazine
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    • v.16 no.9
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    • pp.28-41
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    • 1999
  • 위상배열 안테나 시스템에서 빔 제어 기술은 이동통신 및 위성통신시스템, 비행하고 있는 임의의 비행체의 위치를 고도의 정확도를 가지고 추적하는 군사용 레이더 시스템이나 항공사의 통신 시스템, 선박이나 차량간의 충돌을 방지하기 위한 충돌방지 시스템 등에서 널리 사용되고 있다. 이러한 위상배열 안테나 시스템에서 위상천이기를 이용하는 방법이 널리 사용되고 있다. 이 방법은 원리적으로 간단하지만 실제 구현할 때 위상천이기를 제어하기 위한 제어 신호와 DC 바이어스 라인들 그리고 전력분배기로 구성되어 있기 때문에 전체 회로가 복잡해진다. 뿐만 아니라 현재로서는 위상천이기의 가격과 삽입 손실 때문에 저렴하고 높은 이을 갖는 위상 배열 안테나 시스템을 구현하기가 힘들다. 본 논문에서는 위상천이기를 사용하지 않고 발진기들의 결합을 이용함으로써 이와 같은 단점을 극복하면서 배열 안테나의 복사 빔을 제어할 수 있는 결합발진기 배열 안테나의 최근 기술동향을 분석하고 여러 기술들의 장단점을 기술한다.

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Squint-less Phased Array Antenna Near-field Subwavelength Focusing with True-time Optical Delay Line (광 지연선로를 이용한 스퀸팅이 없는 위상배열 안테나의 근접장 서브파장 포커싱)

  • Jung, Young Jin
    • Korean Journal of Optics and Photonics
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    • v.30 no.3
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    • pp.94-100
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    • 2019
  • The near-field subwavelength squint-less focusing system of a phased array antenna is designed and demonstrated by numerical simulation. The Huygens-Fresnel principle is applied to numerical simulation for calculation of the phased array antenna at microwave frequency. It was shown that beam squinting can be eliminated, utilizing true-time optical delay lines based on a chirped fiber grating in the proposed system. Furthermore, subwavelength focusing with high numerical aperture can be achieved by considering the fact that the array elements of the phased-array antenna can be treated as diffractive elements in an optical lens system. Also, side lobes can be suppressed by decreasing the distance between element antennas to less than half of the wavelength.

Procedure Development and Qualification of the Phased Array Ultrasonic Testing for the Nuclear Power Plant Piping Weld (원자력발전소 배관 용접부 위상배열 초음파검사 절차서 개발 및 기량검증)

  • Yoon, Byung-Sik;Yang, Seung-Han;Kim, Yong-Sik;Lee, Hee-Jong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.4
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    • pp.317-323
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    • 2010
  • The manual ultrasonic examination for the nuclear power plant piping welds has been demonstrated by using KPD(Korean Performance Demonstration) generic procedure. For automated ultrasonic examination, there is no generic procedure and it should be qualified by using applicable automated equipment. Until now, most of qualified procedures used pulse-echo technique and there is no qualified procedure using phased array technique. In this study, data acquisition and analysis software were developed and phased-array transducer and wedge were designed to implement phased array technique for nuclear power plant in-service inspection. The developed procedure are qualified for performance demonstration for the flaw detection, length sizing and depth sizing. The qualified procedure will be applied for the field examination in the nuclear power plant piping weld inspection.

Fabrication of Phased Array EMAT and Its Characteristics (위상배열 EMAT의 제작 및 특성 평가)

  • Ahn, Bong-Young;Cho, Seung-Hyun;Kim, Young-Joo;Kim, Ki-Bok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.4
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    • pp.373-379
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    • 2010
  • EMAT has been applied in various fields for flaw detection and material characterization because it has noncontact property in wave generation and a good mode selectivity. Unfortunately, however, EMAT shows low signal to noise ratio relative to commercial contact transducer because of low energy conversion efficiency. If the phase matching through the control of time delay between each coil consisting of the array EMAT is accomplished, it is expected that it will be a solution for the improvement of low signal to noise ratio. In this experiment, the phased array EMATs which consists of 3 or 4 meander coils and one big magnet were fabricated for surface and vertical shear wave generation. Effect of phased delay control on signal directivity and amplitude enhancement was verified. A slit with the depth of 0.5 mm and a side-drill hole of 0.5 mm diameter were clearly detected by fabricated phased array EMATs, respectively.

The Radiation Characteristics of a Linear Phased Array Antenna using a Pin Array Patch Antenna as an Element (핀 배열 안테나를 단위 안테나로 사용한 선형 위상 배열 안테나의 방사 특성)

  • Kim, Tae-Young;Kim, Gun-Su;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.12
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    • pp.44-51
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    • 2009
  • The radiation characteristics of a pin array patch antenna phased array are compared to those of a conventional patch antenna phased array. The performance of a pin array patch antenna phased array is much improved than that of a conventional patch antenna phased array because the mutual coupling between the adjacent pin array patch antennas is very small compared to that between the adjacent conventional patch antennas. The radiation characteristics of a pin array patch antenna phased array show the superior performance such as low variation of the gain of the main beam and the side lobe level for the variation of the direction of the main beam.

Design and Performance Evaluation of Shear Wave Phased Array Ultrasonic Transducer (횡파 위상배열 초음파 탐촉자 설계 및 성능 평가)

  • Yoon, Byung-Sik;Lee, Hee-Jong;Braconnier, Dominique
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.2
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    • pp.185-191
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    • 2012
  • Typically, a wedge is involved to generate effectively high inspection angle in pipe weld inspection using phased array ultrasonic technique. But the usage of this wedge for weld or access limited area can cause coverage limitation for the examination volume because of the wedge front length. Therefore, the shear wave phased array probe which can generate high inspection angle without wedge is essentially necessary. In this paper, the shear wave phased array ultrasonic probe which can generate high inspection angle designed by modeling and manufactured from the modelling result. And this shear wave probe tested whether it can detect and sizing for EDM test block that contains various depth. As results, the experimental results show that the designed shear wave phased array probe can detect and size with reliable accuracy. Therefore if this phased array probe apply in field inspection, it is expected that it show more reliable inspection result for plant structure having access limitation.

On the implementation of Taper slot array antenna structure (Taper 슬롯구조배열 안테나 구현)

  • Lee, Cheon-Hee;Kim, Ho-Jun;Kwak, Kyung-Sup
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.13 no.1
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    • pp.127-134
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    • 2014
  • X-Band taper slot-typed active phased array antenna is studied and designed. Through the simulated and measured performances, it is confirmed that both of active reflection coefficient and active radiation pattern of the designed phased array antenna are agreed well with those of the prototype manufactured one. From this study, the proposed antenna structure is matched to the design target of characteristics of antenna's broadband beam.

A Parallel Structure Beamformer Using The Compensation for Phase Differences In LOS Environment (LOS환경에서 위상 차이 보상을 이용한 병렬 구조 빔 형성기)

  • 심세준;정성헌;양승철;이충용
    • Proceedings of the IEEK Conference
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    • pp.95-97
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    • 2000
  • 배열 안테나에서 안테나 소자의 개수의 증가는 안테나의 이득을 증가시킬 수 있으므로 열악한 채널 환경에서도 채널이 필요로 하는 링크 마진을 얻을 수 있다. 그러나, 기존 빔 형성기에서 사용되는 배열 안테나 기법은 많은 계산량과 소모 메모리량 때문에 배열 소자의 개수에 제한이 따르게 된다. 이러한 문제를 해결하기 위하여 본 논문에서는 배열 안테나의 구조에 따른 위상차이를 보상하여 적은 계산량과 메모리를 갖는 배열 위상 차이 보상을 이용한 평행 구조 빔 형성기를 제안한다 배열 위상 차이를 보상하는 기법으로 적은 계산량과 메모리로 개수가 많은 긴 배열 안테나에서 얻을 수 있는 분해능과 안테나 이득을 얻을 수 있다. 제안된 기법의 성능을 비교하기 위해 기존의 빔 형성기법으로delay-sum 빔 형성기와 공분산 행렬의 고유치 해석을 통한 고유벡터 기법의 빔 스펙트럼과 연산량을 비교하였다. 제안된 기법으로 빔 형성을 하면, 배열 안테나의 소자의 개수가 늘어나도 기존의 방법보다 최소 30%의 연산량으로 스펙트럼 상 비슷한 성능을 얻을 수 있다.

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A New Beam Tracking Technique Using Intermediate Frequency Processing (중간주파수 처리를 이용한 빔추적 능동위상 배열안테나)

  • 서철헌;최태규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.7B
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    • pp.891-894
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    • 2001
  • 본 논문에서는 능동 배열 안테나에서 RF 대신 중간주파수를 이용하여 빔 추적을 하는 방법이 연구되었다. 안테나의 각 배열은 전압제어 발진기, 위상추적기, 혼합기와 결합되어 있으며 혼합기는 안테나 상에서 직접 RF 신호를 직접 중간주파수 신호로 변환시킨다. 전압제어 발진기 입력은 위상추적기에 의하여 조절되며 배열 안테나의 주사범위는 위상추적기와 전압제어발진기에 의하여 결정되었다.

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