• Title/Summary/Keyword: 평면 배열

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Molecular Orientation of Evaporated Pentacene Film on Polyimide Alignment Layer (폴리이미드 배향막에 증착된 Pentacene 분자의 배향 연구)

  • Kim Beom-Kyung;Kim Do-Hoi;Chung Jae-Sun;Kim Young-Ju;Seo In-Seon;Kwon Soon-Ki;Song Ki-Gook
    • Polymer(Korea)
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    • v.30 no.4
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    • pp.362-366
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    • 2006
  • It was found by polarized FTIR spectroscopic studies that pentacene molecules are arranged with their molecular axes perpendicular to the substrate surface when pentacene films are deposited on a polyimide alignment layer. The ring plane in a pentacene molecule is arranged parallel to the rubbing direction of the polyimide alignment film while no specific arrangement of vertically deposited pentacene molecules was found for the film without rubbing. The pentacene band at $1296cm^{-1}$ which has a transition dipole moment parallel to the ring plane is much stronger in a polarized IR spectrum of parallel to the rubbing direction, whereas the band at $908cm^{-1}$ whose transition dipole align normal to the ring plane shows much stronger intensity in a spectrum of perpendicular to the rubbing direction. These findings indicate that orientation of polyimide chains affects the arrangement of pentacene molecules when they are deposited on a polyimide alignment film.

Base Station Antenna with Rectangular Radiation Pattern using Strip Feeding Planar Monopole Array (스트립 급전 평면 모노폴 배열을 이용한 직사각형 방사패턴 기지국용 안테나)

  • 신헌철;문상만;우종명
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.6
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    • pp.1018-1024
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    • 2001
  • In this paper, an array antenna is designed far base station of a street micro-cell in urban areas. It has a rectangular radiation pattern. The current distribution of the array is decided by using a modified Woodward-Lawson sampling pattern synthesis method. To confirm the realization of the array antenna with rectangular pattern, 12 array antenna with a planar type monopole fed by stripline is fabricated and measured. In the results of the measured values, H-plane pattern of the antenna nearly yields a rectangular radiation pattern.

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Design and Fabrication of the Oscillator Type Active Antenna by Using Slot Coupling (슬롯결합을 이용한 발진기형 능동 안테나의 설계 및 제작)

  • Mun, Cheol;Yun, Ki-Ho;Jang, Gyu-Sang;Park, Han-Kyu;Yoon, Young-joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.1
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    • pp.13-21
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    • 1997
  • In this paper, the oscillator type active antenna used as an element of active phased array antenna is designed and fabricated using slot coupling. The radiating element and active circuit are fabricated on each layer respectively and coupled electromagnetically through slot on the ground plane. This structure can solve the problems such as narrow bandwidth of microstrip antenna, spurious radiation by active circuits, and spaces for integration of the feeding circuits which are caused by integrating antennas with oscillator circuits in the same layer. The active antenna in this paper, the oscillation frequency can be tuned linearly by controlling the drain bias voltage of FET. The frequency tuning range is between 12.37 GHz to 12.65 GHz when bias voltage is varied from 3V to 9V, thus frequency tuning bandwidth is 280 MHz (2.24%). The output power of antenna is uniform within 5dB over frequency tuning range. Therefore this active antenna can be used as an element of linear or planar active phased array antennas.

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DOI Detector Design using Different Sized Scintillators in Each Layer (각 층의 서로 다른 크기의 섬광체를 사용한 반응 깊이 측정 검출기 설계)

  • Seung-Jae, Lee
    • Journal of the Korean Society of Radiology
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    • v.17 no.1
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    • pp.11-16
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    • 2023
  • In preclinical positron emisson tomography(PET), spatial resolution degradation occurs outside the field of view(FOV). To solve this problem, a depth of interaction(DOI) detector was developed that measures the position where gamma rays and the scintillator interact. There are a method in which a scintillation pixel array is composed of multiple layers, a method in which photosensors are arranged at both ends of a single layer, a method in which a scintillation pixel array is constituted in several layers and a photosensor is arranged in each layer. In this study, a new type of DOI detector was designed by analyzing the characteristics of the previously developed detectors. In the two-layer detector, different sizes of scintillation pixels were used for each layer, and the array size was configured differently. When configured in this form, the positions of the scintillation pixels for each layer are arranged to be shifted from each other, so that they are imaged at different positions in a flood image. DETECT2000 simulation was performed to confirm the possibility of measuring the depth of interaction of the designed detector. A flood image was reconstructed from a light signal acquired by a gamma-ray event generated at the center of each scintillation pixel. As a result, it was confirmed that all scintillation pixels for each layer were separated from the reconstructed flood image and imaged to measure the interaction depth. When this detector is applied to preclinical PET, it is considered that excellent images can be obtained by improving spatial resolution.

The Design of Electronically Beam Steeling Array Antenna Using 4 Parasitic Elements (4개의 기생 소자를 이용한 전자적인 빔 조향 배열 안테나 설계)

  • Kim, Young-Goo;Choi, Ik-Guen;Kim, Tae-Hong;You, Jong-Jun;Kang, Sang-Gee
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.2
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    • pp.167-173
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    • 2009
  • This paper proposes an electronically beam steering array antenna, consisting of single fed active element and 4 parasitic elements, operating in 5.8 GHz ISM band. Beam steering can be achieved by controlling the reactance of the variable reactance control circuit connected to the load of the parasitic elements without using the high cost phase shifters. The proposed antenna realizes ${\pm}30^{\circ}$ beam scanning of E-plane and H-plane with the below -10 dB return loss in ISM band. The gain of the $6.18{\sim}7.53\;dBi$ in E-plane and $7.022{\sim}7.779\;dBi$ in H-plane is shown in the scanning range.

An Experimental Study on the improvement of harbor tranquility by Multi-cylinder piles Structure (다원주 파일군 구조물에 의한 항내 정온도 향상에 관한 실험적 연구)

  • Lee, Sang-Hwa;Jang, Eun-Cheul;Jeong, Dong-Hwa
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.1
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    • pp.66-72
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    • 2007
  • In order to control waves in coastal zones effectively, multi-cylinder piles as the economical structures are suggested. A three dimensional hydraulic model experiment was performed to investigate the hydraulic characteristics of the structure. An experimental study was carried out research the effect of wave control and harbor tranquility through the wave height analysis for the existing concrete wave breaker and the structure with acrylic multi-cylinder piles type at the same location. In the results, the effective order of harbor tranquility is shown as the wave breaker > the staggered arrangement of multi-cylinder piles > the regular arrangement of multi-cylinder piles.

The Design of Planar Beam Tilt Antenna for Satellite up-link Communication in Ka-band (Ka-band 위성통신 up-link 용 평면형 빔틸트 안테나의 설계)

  • Lim, Gye-jae
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.5 no.3
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    • pp.101-109
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    • 2012
  • Because the installation problem of parabola antenna that is tilted to 45 degree when this antenna is installed at the area of middle latitude, the study on planar antenna in place of parabola antenna is made rapid progess. Especially, The development of the planar antenna for VSAT is needed depending on the increased Ka-band satellite communications. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. Especially, for the lower sidelobe level, the design method of the radiation power distribution control using the different slot widths is proposed. An array antenna consisting of 32 leakywave waveguide antennas is showing 35.16 dBi of gain, 2.5 degree of beamwidth at azimuth, below than -30 dB of sidelobe level, 45.8 degree of beam tilt angle in center frequency 30.2 GHz.

Calculation of the Mutual Radiation Impedance by the Spatial Convolution in the Cylindrical Structure (원통 구조에서 공간 콘볼루션을 이용한 상호 방사 임피던스 계산)

  • Bok, Tae-Hoon;Li, Ying;Paeng, Dong-Guk;Lee, Jong-Kil;Shin, Ku-Kyun;Joh, Chee-Yong
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.1
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    • pp.1-9
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    • 2010
  • The mutual radiation impedance was calculated using the spatial convolution in the cylindrical structure. The Cartesian coordinate was transformed into the cylindrical coordinate using the spatial convolution for the cylindrical array structure. This method cannot consider the cylindrical baffle, but can reduce the computation time. The error for not considering the cylindrical baffle was analyzed by the comparison of the spatial convolution method with the quadruple integration method in the cylindrical structure. The mutual radiation resistance in the cylindrical structure was compared with the one in the planar baffle. Based on two kinds of the comparison, we presented the error of the suggesting method in this paper, confirming that the spatial convolution method could be applied to compute the mutual radiation impedance in the cylindrical structure at certain conditions.

Dual-Band Array Antenna Using Modified Sierpinski Fractal Structure (변형된 Sierpinski 프랙탈 구조를 갖는 이중 대역 배열 안테나)

  • Oh, Kyung-hyun;Kim, Byoung-chul;Cheong, Chi-hyun;Kim, Kun-woo;Lee, Duk-young;Choo, Ho-sung;Park, Ik-mo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.9
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    • pp.921-932
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    • 2010
  • This paper presents a dual-band array antenna based on a modified Sierpinski fractal structure. Array structure is mirror symmetric, and forms broadside radiation pattern for dual frequency band if the ports are fed with $180^{\circ}C$ phase difference between upper and lower $2{\times}1$ array. To use in-phase corporate feeding circuit, the phase inversion structure is designed by changing the position of patch and ground for upper and lower array. The dimensions of the array antenna is $28{\times}30{\times}5\;cm^3$ and the bandwidth of 855~1,380 MHz(47 %), 1,770~2,330 MHz(27 %) were achieved for -10 dB return loss. The measured gain is 9.06~12.44 dBi for the first band and 11.76~14.84 dBi for the second band. The half power beam width is $57^{\circ}$ for x-z plane and $46^{\circ}$ for y-z plane at 1,100 MHz and $43^{\circ}$ and $28^{\circ}$ at 2,050 MHz, respectively.

Study on Pattern Synthesis of Conformal Phased Array Antenna (컨포멀 위상 배열 안테나의 패턴 합성에 대한 고찰)

  • Park, Dong-Chul;Kwon, Oh-Hyuk;Ryu, Hong-Kyun;Lee, Kyu-Song
    • 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.