• Title, Summary, Keyword: Slotted Arrays

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An Optimal Parallel Algorithm for Generating Computation Tree Form on Linear Array with Slotted Optical Buses (LASOB 상에서 계산 트리 형식을 생성하기 위한 최적 병렬 알고리즘)

  • Kim, Young-Hak
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.5
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    • pp.475-484
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    • 2000
  • Recently, processor arrays to enhance the banRecently, processor arrays to enhance the bandwidth of buses and to reduce the complexity of hardwares, using optical buses instead of electronic buses, have been proposed in manyliteratures. In this paper, we first propose a constant-time algorithm for parentheses matching problemon a linear array with slotted optical buses (LASOB).Then, given an algebraic expression of length n, we also propose a cost optimal parallel algorithmthat constructs computational tree form in the steps of constant time on LASOB with n processorsby using parentheses matching algorithm. A cost optimal parallel algorithm for this problem that runsin constant time has not yet been known on any parallel computation models.

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A Circularly Polarized Waveguide Narrow-wall Slot Array using a Single Layer Polarization Converter

  • Kim, Dong-Chul;Min, Kyeong-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.1
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    • pp.59-65
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    • 2000
  • This paper describes the characteristics of a one dimensional narrow-wall slotted waveguide array with a single-layer linear-to-circular polarization converter consisting of a dipole array. An external boundary value Problem of one slot and three dipoles, which approximates the mutual coupling between the dipole array and an edge slot extending over three faces of a rectangular waveguide, is formulated and analyzed by the method of moments; design of polarization conversion is conducted for this model as a unit element. If every unit element has perfect circular polarization, grating lobes appear in the array pattern due to the alternating slot angle: these are suppressed in this paper by changing the dipole angle and degrading the axial ratio of the unit element. The validity of the design is confirmed by the measurements. The dipole array has negligible effects upon slot impedance; the polarization conversion for existing narrow-wall slotted arrays is realized by add-on dipole array.

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A Slot Away Antenna with a Simple Feed Structure for Broadband Multimedia Wireless Applications (단순한 급전 구조를 갖는 Broadband Multimedia Wireless System(BMWS)용 슬롯 배열 안테나)

  • 성영제;이정수;오순수;문종용;최원규;표철식;최재익;김영식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.3
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    • pp.209-216
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    • 2003
  • We design and fabricate slot array antenna for BMWS(Broadband Multimedia Wireless System) applications. This paper presents a simple feed structure, which consists of two horns and a parallel-plate waveguide, because antennas operating at 40.5 GHz~43.5 GHz have considerable feeding losses. The simple feed structure has the advantages of high-efficiency and mass-production. The fabricated antenna has a gain of 25.8 dBi with a sidelobe level below -18 ㏈ and a 3 ㏈ beamwidth of approximately 3$^{\circ}$ in the E-plane. In case of H-plane, a 3 ㏈ beamwidth is 17$^{\circ}$ and a sidelobe level is suppressed to below -27 ㏈. The experimental results are in good agreement with the simulation results. The authors expect that narrow 3 ㏈ beamwidth is obtained by combining a few proposed slot array antennas in parallel.

Frequency determination for beam command in rotating phase and frequency scan radar systems (회전 위상-주파수 주사 레이다 시스템의 빔 명령을 위한 주파수 결정)

  • 이민준;박정순;송익호;김광순;장태주
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.5
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    • pp.1319-1324
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    • 1998
  • The phase and frequency commands of a ratating radar system that utilizes frequency scanning to steer the beam in the azimuth direction and phase shifters in the elevation direction are derived in terms of the angles of the groung based coordinate system. The antenna type considered is slotted arrays that are easy to construct at such high microwave frequency as the X band. The frequency that has non-linear characteristics as a functio ofthe elevation angle is plotted and the derived frequency equation is aproximated to be a simple form to reduce the calculation time for real time multi-function radar systems. It is shown that the approximated frequency command is in good agreement with the exact one if the range of azimuth scanning is limited by ${\pm}10^{\circ}$.

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