• Title, Summary, Keyword: 방사패턴

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Base Station Antenna of Radiation Pattern for the Cruciform using Monopole Array (도심지 교차로 지형에 맞는 방사패턴 형성을 위한 기지국용 모노폴 어레이 안테나)

  • 문상만;우종명;신헌철
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.9
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    • pp.964-970
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    • 2002
  • In this paper, cruciform radiation pattern antenna was designed and fabricated. The fabricated antenna is applicable to intersections which is composed of four eight-lane roads each having 60 m of width and 200 m of length. The design theory was based on Woodward-Lawson method and the 6 monopole elements with the strip feeding network are made by linear array on the micro-strip board. In the results, - 13.5 dB of return loss and 120 MHz(6 %) of -10 dB bandwidth were obtained at the 2 GHz. Also, at 1.95 GHz, -6 dB of gain fall was seen at $\pm$45$^{\circ}$ and thus, it is possible to say that the presented antenna has well-shaped cruciform radiation pattern.

Acoustic Radiation Analysis of Stiffened Cylindrical shell and Vibrational Velocity by FFT (보강 원통형 몰수체의 음향방사 해석과 FFT에 의한 진동 해석)

  • 배수룡;이헌곤;홍진숙
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.128-133
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    • 1993
  • 본 연구에서는 보강 원통쉘에 대하여 주위 유체의 영향을 고려하여 진동 및 음향방사를 해석하였다. 원통셀의 운동방정식은 Donnell 이론을 적용하였으 며, Contour 적분을 풀지 않고 FFT 알고리즘(Fast Fourier Transform Algorithm)을 이용하여 원통쉘의 진동을 계산하였다. 현재까지의 방사패턴에 관한 연구는 주로 원주 방향에 집중되어 왔으나, 보강 원통쉘의 방사패턴은 원추파 모형에 가까우므로 극좌표 .theta. 방향에 대한 음향방사 패턴에 관한 연구가 이루어져야 한다. 그러므로, 본 연구에서는 극좌표에 관한 방사패턴 에 관하여 주로 고찰하였다.

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Theoretical Calculation on Radiation Patterns of Epi-signal in CARS Microscopy (간섭성 반스톡스 라만 산란 현미경 후방 신호지 방사패턴에 관한 이론계산 연구)

  • Yoo, Yong-Shim;Cho, Hyuck
    • Korean Journal of Optics and Photonics
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    • v.18 no.4
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    • pp.286-291
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    • 2007
  • We theoretically investigated the far-field radiation pattern of epi-signal from a polystyrene sphere in coherent anti-Stokes Raman scattering (CARS) microscopy with an objective lens of high numerical aperture. We calculated the field distribution of the incident laser beams under the tight-focusing condition and the far-field radiation pattern through coherent addition of radiation from the nonlinear polarizations (Hertzian dipoles) as the origin of CARS signal generation. The epi-radiation patterns for polystyrene spheres of different diameters are calculated, and the pattern of a sphere is also compared with that of a shell fer a diameter of 1100 nm. We finally show how the radiation pattern of the polystyrene sphere changes as the center of the sphere shifts from the focus of the beam.

Compensation of Radiation Pattern Distortion by Mutual Coupling in the Array Antenna Using the Particle Swarm Optimization Algorithm (입자군집 최적화 알고리즘을 이용한 배열안테나의 상호결합에 의한 방사패턴 왜곡보상)

  • Kim, Jae Hee;Ahn, Chi-Hyung;Chun, Joong-Chang
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.5
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    • pp.458-464
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    • 2016
  • This paper proposes the compensation method which decreases the radiation pattern distortion caused by the mutual coupling in an array antenna. If the element distance of an array antenna decreases, the radiation pattern could be distorted by the strong mutual coupling, which changes the magnitude and phase of input signals and causes an unwanted radiation pattern. To remove the pattern distortion, compensated input signals are inserted in an array antenna. The magnitude and phase of input signals are determined by Particle Swarm Optimization (PSO) algorithm. A $4{\times}1$ dipole array antenna with omnidirectional elements is used to confirm the validity of the algorithm, where each element is placed in 0.2 wavelength to evoke the strong coupling. After input signals are optimized by PSO, it is found that the compensated radiation results in the same as the ideal case.

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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Estimation of Far-field Radiation by 2-Dimensional EM Scattering (2차원 전자파 산란에 따른 방사패턴의 추정)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.51-52
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    • 2014
  • Non-destructive technique to measure internal structure and constant distribution of material can be widely used to exploration of mineral resources, identification of underground cables and buried pipelines, and diagnostic imaging in medical area. In this paper, we considered 2-dimensional EM scattering problem. Radiation pattern in far field is estimated by using some measured information obtained from near-field solutions.

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Analysis of the Radiation Pattern in Relation to the Head Mass Shape Applicable to a Tonpilz Transducer (Tonpilz 트랜스듀서에 적용 가능한 전면추 형상에 따른 방사 패턴 해석)

  • Kim, Hoe-Yong;Roh, Yong-Rae
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.7
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    • pp.422-430
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    • 2010
  • The radiation property of a Tonpilz transducer is influenced by the structural variables of the transducer. In this study, with respect to a single mode Tonpilz transducer, the radiation patterns were calculated for different head mass geometries of the same effective radiation area. The shapes of the head mass analyzed were the most popular circular, regular triangular, square, regular hexagonal and regular octagonal types, and radiation pattern equations were derived for each of the head mass shapes. Based on the derived equations, radiation patterns in accordance with the shape and size of the head mass were calculated and the results were compared with each other. Validity of the calculation results were confirmed by means of finite element analysis.

The Mirror Active Element Pattern Method for The Radiation Pattern Computation of Linear Array Antennas (선형 배열 안테나의 방사패턴 계산을 위한 Mirror Active Element Pattern 방법)

  • Kim, Jae-Hyun;Yoon, Young-Min;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.94-102
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    • 2013
  • We propose the mirror active element pattern (AEP) method for the radiation pattern computation of linear array antennas versus scan angles. The computation time for the radiation pattern of linear array antennas using the mirror AEP method is reduced by almost half compared to that using the AEP method because the number of AEPs of elements obtained by the full-wave simulation necessary for the radiation pattern computation of linear array antennas is reduced by almost half. The difference between the radiation patterns of linear array antennas obtained by the full-wave simulation and mirror AEP method is very small for wide scan angle range when the radiation pattern of an antenna element is symmetric.

Design of Radiation Pattern Reconfigurable Antenna for Vital Signal Sensing Device Attached on Wristband and SAR Analysis on Human body (팔목 부착형 생체신호 측정기기에 사용가능한 방사패턴 재구성 안테나 설계 및 인체 SAR 영향 분석)

  • Lee, Chang Min;Jung, Chang Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.666-670
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    • 2015
  • This paper presents radiation pattern reconfigurable antenna for Fitbit Flex wristband which detects vital signal. Also, the paper presents Specific Absorption Rate (SAR) from the loop-dipole radiation pattern reconfigurable antenna based on the position of human body. The proposed loop-dipole radiation pattern reconfigurable antenna produces two opposite side direction radiation pattern using two RF switches. The resonant frequency of the radiation pattern reconfigurable antenna is Bluetooth communication bandwidth (2.4 - 2.485 GHz) and the maximum gain of the proposed antenna is 1.96 dBi. The proposed antenna satisfied the standard SAR value of 1.6 W/kg in 1 g tissue of the human body when the Bluetooth communication input average power of 0.04 W is excited to five parts of human body (head, chest, stomach, back, wrist). The maximum SAR value of in this simulation is presented in the part of head.

A Study on Monopole Antenna Radiation Pattern inside Vehicle (차량 내부에서의 모노폴 안테나 방사패턴 연구)

  • Lee, Tae-Hak;Pyo, Seong-Min;Park, Sang-Myeong;Kim, Young-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.11
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    • pp.4537-4542
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    • 2010
  • In this paper, the antenna radiation pattern inside the vehicle is presented for observing the change occurring in non-anechoic environment using monopole antenna. The environment for radio communication can be affected by antenna characteristic variation inside the small space existing multi reflection waves. To perform simulation and measurement about antenna radiation pattern, the radio frequency bands for GPS and Wibro services expected to use inside the vehicle is selected. The simulation is based on the ray-tracing method and the radiation pattern is measured inside the vehicle and in free space using monopole antenna having those frequency bands. In accordance with the measurement and simulation results, when two antennas are put inside the vehicle, the omni-directional characteristic of the antenna is maintained but the received power is increased than free space case and the difference between the each case of measurements is increased as the operating frequency is increased.