• Title, Summary, Keyword: 적층배열

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A Study on Optimization of a Multi-Layered Metallic Disk Array Structure for Shaping of Flat-Topped Element Patterns (구형 빔 패턴 형성을 위한 다층 원형 도체 배열 구조의 최적화 연구)

  • 엄순영;박한규
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.10
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    • pp.985-995
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    • 2003
  • In this paper, a study on optimization of three dimensional multi-layered metallic disk array structure(MDAS) excited by circular waveguides was performed to shape efficient flat-topped element patterns(FTEP) of ${\pm}$20$^{\circ}$ beam width. Each radiating element of the MDAS is composed of input, transition and radiation circular waveguides and finite metal disks stacked on radiation circular waveguide. It has an array structure of a hexagonal lattice appropriate for the conical beam scanning. The analytic algorithm for the MDAS was proposed and the code was also programmed using it. Optimal design parameters of the MDAS were determined through the optimal simulation process to obtain ${\pm}$20$^{\circ}$ FTEP. Also, bandwidth characteristics for FTEP and reflection coefficients of the MDAS were investigated and, as the results, it was shown that the MDAS could shape good FTEPs of ${\pm}$20$^{\circ}$ beam width in main planes at least within a 5.6 % frequency band.

The Low Sidelobe Array Antenna Design of Mobile Antenna System for Satellite Multimedia Communications (위성 양방향 통신용 이동 안테나 시스템의 저부엽 특성 배열 안테나 설계)

  • Park Ung Hee;Son Seong Ho;Noh Haeng Sook;Jeon Soon Ik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.1
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    • pp.91-97
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    • 2005
  • In the mobile antenna systems for satellite multimedia communications, the active way antenna having a low sidelobe antenna pattern is described in this paper. This designed and fabricated array antenna is satisfied with international beam pattern regulation on moving states. The subarray of the proposed mobile antenna system is arranged with a stair-planar structure and non-periodic array spacing. This subarray is designed with three-layered microstrip patch as both receiving and transmitting radiator of which are improved with antenna gain and bandwidth. Also, the optimum subarray spacing is designed to make the lowest sidelobe pattern by genetic algorithm. In addition, the characteristics of a GA-perturbed array are investigated from simulated and measured beam pattern results.

Discrete Optimization of Unsymmetric Composite Laminates Using Linear Aproximation Method (선형 근사화방법을 이용한 비대칭 복합 적층평판의 이산최적화)

  • 이상근;구봉근;한상훈
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.255-263
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    • 1997
  • The optimum design of most structural systems used in practice requires considering design variables as discrete quantities. The present paper shows that the linear approximation method is very effective as a tool for the discrete optimum designs of unsymmetric composite laminates. The formulated design problem is subjected to a multiple in-plane loading condition due to shear and axial forces, bending and twisting moments, which is controlled by maximum strain criterion for each of the plys of a composite laminate. As an initial approach, the process of continuous variable optimization by FDM is required only once in operating discrete optimization. The nonlinear discrete optimization problem that has the discrete and continuous variables is transformed into the mixed integer programming problem by SLDP. In numerical examples, the discrete optimum solutions for the unsymmetric composite laminates consisted of six plys according to rotated stacking sequence were found, and then compared the results with the nonlinear branch and bound method to verify the efficiency of present method.

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Critical Buckling Temperatures of Anisotropic Laminated Composite Plates considering a Higher-order Shear Deformation (고차전단변형을 고려한 비등방성 적층복합판의 임계좌굴온도)

  • Han, Seong Cheon;Yoon, Seok Ho;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2
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    • pp.201-209
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    • 1998
  • The presence of elevated temperature can alter significantly the structural response of fibre-reinforced laminated composites. A thermal environment causes degradation in both strength and constitutive properties, particularly in the case of fibre-reinforced polymeric composites. Furthermore, associated thermal expansion, either alone or in combination with mechanically induced deformation, can result in buckling, large deflections, and excessively high stress levels. Consequently, it is often imperative to consider environmental effects in the analysis and design of laminated systems. Exact analytical solutions of higher-order shear deformation theory is developed to study the thermal buckling of cross-ply and antisymmetric angle-ply rectangular plates. The buckling behavior of moderately thick cross-ply and antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Numerical results are presented for fiber-reinforced laminates and show the effects of ply orientation, number of layers, plate thickness, and aspects ratio on the critical buckling temperature and compared with those obtained using the classical and first-order shear deformation theory.

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Design of Microstrip array antennas for Tx/Rx dual operation at X-band (X-band 송/수신 겸용 마이크로스트립 배열 안테나 설계)

  • 노행숙;윤재승;전순익
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.12C
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    • pp.1299-1305
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    • 2002
  • Tx/Rx dual microstrip array antennas for satellite communications are designed, fabricated, and measured in this paper. They have a Right Handed Circular Polarization (RHCP) for Tx and Left Handed Circular Polarization (LHCP) for Rx. Two stacked patches are used for wideband characteristics and corner-truncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, 2${\times}$1 sequential rotation mays are applied. From the measured results, 8${\times}$1 microstrip may antennas have a good agreement with those of the simulation. Therefore the array antennas are applicable to satellite communication antennas, active phased may antennas, and radiators in other antennas.

Satellite Communication Microstrip Antenna for Tx/Rx Dual Operation at X-Band (X 대역 위성통신 송/수신 겸용 마이크로스트립 안테나)

  • Kim, Kun-Woo;Lee, Sung-Jae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.2
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    • pp.164-171
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    • 2014
  • Transmit(Tx)/Receive(Rx) dual band operation microstrip array for X-band satellite communications are designed, fabricated, and measured in this paper. The microstrip array antenna has Right Handed Circular Polarization(RHCP) for Tx band and Left Hand Circular Polarization(LHCP) for Rx band. Two stacked patches are used for wideband characteristics and corner-truncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, $2{\times}2$ sequential rotation array are applied. From the measured result, $8{\times}12$ microstrip array antennas have a good agreement with those of the simulation. Therefore the array antennas are applicable to military satellite communication antennas.

An Aperture Coupled Microstrip Array Antenna Design for X-Band Radar Applications (X-band 레이더 응용을 위한 개구면 결합 급전 마이크로스트립 배열 안테나 설계)

  • Yoon, Won-Sang;Hong, Min-Cheol;Lee, Ju-Heun
    • 한국정보기술학회논문지
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    • v.15 no.4
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    • pp.23-29
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    • 2017
  • In this paper, an aperture coupled microstrip array antenna applicable to X-band radar systems is described. Eight unit radiators and a 8-way Wilkinson divider consist of the proposed array antenna. The unit radiator is composed by two stacked substrates using common ground plane with aperture slot and two rectangular patches and feeding network using T-junction divider is etched on each substrates. Two substrates including two patches and feeder network are bonded using a prepreg for obtaining solid structure. From the experimental results, the fabricated array antenna has an impedance bandwidth of 9.19~9.78GHz and a maximum gain of 14.7dBi in the operating band. Also, the 3dB beamwidth is measured $12.5^{\circ}$ at 9.35GHz.

Design and Fabrication of Linear-Array Ultrasonic Transducer Using KLM and FEM Simulation for Non-Destructive Testing (KLM 및 FEM 시뮬레이션을 이용한 비파괴검사용 선형배열 초음파 탐촉자의 설계 및 제작)

  • Park, Chan-Yuk;Sung, Jin-Ho;Jeong, Jong-Seob
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.2
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    • pp.120-127
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    • 2015
  • In this paper, a linear-array transducer capable of overcoming the faults of a single element and phased array transducers with convex shape for non-destructive ultrasonic testing was designed and fabricated. A 5.5 MHz linear-array transducer was designed using the PiezoCAD program based on the KLM analysis and the PZFlex program based on the FEM analysis. A 2-2 composite structure was employed to achieve broad-band characteristics. A 128 element linear-array transducer was fabricated and its performance was compared with the simulation results. The center frequency of the fabricated transducer was 5.5 MHz and the -6 dB frequency bandwidth was 70 %. Thus, we expect that the designed transducer can provide an effective inner image of the test material during non-destructive ultrasonic testing.

Analysis and Implementation of the Stacked Cavity-Backed Circular Microstrip Patch Antenna (적층형 Cavity-Backed 원형 마이크로스트립 안테나 해석 및 구현에 관한 연구)

  • 박경빈;정영배;최동혁;박성욱;문영찬;전순익
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.1
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    • pp.37-45
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    • 2000
  • Though microstrip antenna has several advantages, it makes engineers struggle against the difficulties of narrow bandwidth and scan-blindness with probe-feeding and array configuration. To overcome these disadvantages, stacked patch and cavity-backed structure had been proposed. But this structure can not be analyzed easily because we have no concrete means to analyze it. So the algorithm to analyze the structure should be established to make it useful. This paper explained the algorithm of moment method to analyze the structure and verified it by comparing the calculated and measured results.

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Optimal Ply Design of Laminated Composite Plate with a Hole Considering Vibration (진동을 고려한 원공복합적층판의 최적적층설계)

  • 홍도관;김동영;최경호;안찬우
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.6
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    • pp.423-429
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    • 2003
  • On this study. we improved the efficiency applying algorithm that is repeatedly using table of orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result of optimization achievement repeatedly using statistical table of orthogonal array of experimental design and the BFGS optimal design method.