• Title/Summary/Keyword: Short Dipole

Search Result 45, Processing Time 0.027 seconds

Antenna factors of short dipole antennas with roberts balun (Roberts밸런을 갖는 단축 다이폴 안테나의 안테나 인자)

  • 김기채
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.22 no.3
    • /
    • pp.532-538
    • /
    • 1997
  • Exactly aclculated antenna factors are requeired for determining EMI levels in an actual radiated emission test. In this paper, the antenna factors of short dipole antennas above the ground plane are calculated theoretically for the antenna with Roberts balun specified ANSI C63.5 regulation. Also treated is a half-wavelength dipole antenna with Roberts balun to compare the antenna factors with those of resonant dipole antenna. In formulationof antenna factors the antenna is treated as the boundary value problem of Maxwells equations and is analyzed by the Galerkins method of moments. The balun is treated using circuit theory based on power transmission mismatch.

  • PDF

Short-Ended Electromagnetically Coupled Coaxial Dipole Array Antenna

  • Kim, Joong-Pyo;Lee, Chang-Won
    • Journal of electromagnetic engineering and science
    • /
    • v.2 no.2
    • /
    • pp.87-92
    • /
    • 2002
  • A short-ended electromagnetically coupled coaxial dipole array antenna is investigated theoretically. The antenna has an advantage of structural simplicity. The integral equations are derived for the proposed structure by use of the Fourier transform and mode expansion, and the simultaneous linear equations are obtained. The slot electric field and strip current are obtained by solving the simultaneous linear equations. The effects of slot and strip numbers on the radiation efficiency, beamwidth and directivity gain of the antenna are presented.

Design and Fabrication of an Electric-Field Probe Using Short Dipole Antennas (소형 이극안테나를 이용한 전계강도 프로브의 설계 및 제작)

  • 김혁제;박동철;이애경;심환우
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.6 no.1
    • /
    • pp.3-9
    • /
    • 1995
  • An isotropic electric-field probe, capable of characterizing and quantifying electromagnetic field, was fabricated. The probe consists of three short dipole antennas, a beam-lead Schottky diode and the high resistive transmission line. In order to get the isotropic response three mutually orthogonal dipoles are configured to form the probe. The probe's short dipole elements allow measurements of electric fields from 300MHz to 2GHz with a flatness of .+-. 2.9dB. The mutually orthogonal dipole configration shows a .+-. 1.2dB deviation in the isotropic response with respect to angle.

  • PDF

Poly-gate Quantization Effect in Double-Gate MOSFET (폴리 게이트의 양자효과에 의한 Double-Gate MOSFET의 특성 변화 연구)

  • 박지선;이승준;신형순
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.8
    • /
    • pp.17-24
    • /
    • 2004
  • Quantum effects in the poly-gate are analyzed in two dimensions using the density-gradient method, and their impact on the short-channel effect of double-gate MOSFETs is investigated. The 2-D effects of quantum mechanical depletion at the gate to sidewall oxide is identified as the cause of large charge-dipole formation at the corner of the gate. The bias dependence of the charge dipole shows that the magnitude of the dipole peak-value increases in the subthreshold region and there is a large difference in carrier and potential distribution compared to the classical solution. Using evanescent-nude analysis, it is found that the quantum effect in the poly-gate substantially increases the short-channel effect and it is more significant than the quantum effect in the Si film. The penetration of potential contours into the poly-gate due to the dipole formation at the drain side of the gate corner is identified as the reason for the substantial increase in short-channel effects.

3-Axial Isotropic Electric-Field Probe Design with Resistor-Loaded Short Dipole (저항 부하된 소형 다이폴을 이용한 3축 등방성 전기장 프로브 설계)

  • Moon, Sung-Won;Jang, Byung-Jun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.28 no.3
    • /
    • pp.246-249
    • /
    • 2017
  • In this paper, we designed the 3-axis isotropic electric-field measurement probe using resistor-loaded short dipole with lumped chip resistors. The designed probe shows good isotropic characteristics as well as wideband and low sensitivity. The isotropic characteristics of ${\pm}0.39dB$ from 100 kHz to the 3 GHz band were derived and the reception sensitivity was 0.1 V/m. The frequency response is within 3 dB of the whole section, especially ${\pm}1.3dB$ from 150 kHz to 3 GHz, which is superior to the conventional electric field probe with short dipoles.

Forced Resonant Type EMI Dipole Antennas for Frequencies Below 80 MHz

  • Kim, Ki-Chai
    • Journal of electromagnetic engineering and science
    • /
    • v.2 no.1
    • /
    • pp.45-49
    • /
    • 2002
  • This paper presents the basic characteristics of a forced resonant type EMI dipole antennas for frequencies below 80 MHz in which two reactance elements are used for the impedance matching at the fined point. The input impedance of the short dipole less than half-wavelength is controlled by the properly determined loading position and the value of loading reactance. The numerical results show that the small-sized EMI dipole antenna with loller antenna factors for frequencies below 80 MHz can be realized by the reactance loading. In case tole proposed center driven forced resonant type EMI dipole antenna with 0.3 λ length is loaded from the center, the input impedance is matched at feed line with 50 $\Omega$, and hence the antenna has lower factors in the frequency range of 30 to 80 MHz.

Analysis and Characteristics of Log-Periodic X Dipole Antennas (대수주기 X 다이폴 안테나의 해석 및 특성)

  • 최학근
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.10 no.3
    • /
    • pp.329-339
    • /
    • 1999
  • LPXDA(Log-Periodic X Dipole Antenna), consisting of X dipole elements, was proposed as a Log-periodic antenna with short boom length and good Performance relative to LPDA(Log-Periodic Dipole Antenna) . LPXDA for operating frequency band of 500 MHz~l,000 MHz was designed and radiation characteristics of the designed antenna was analyzed by moment method, and compared with LPDA characteristics. The proposed LPXDA, in this paper, was found to have shorter boom length by 20% and better radiation characteristics with variations of frequency relative to the LPDA. The calculated results show good agreement with measurements.

  • PDF

Analysis of electrically-short dipole in consideration of conductor loss (도체 손실을 고려한 매우 짧은 쌍극자 안테나의 특성 해석)

  • 김영국;이해영
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.32A no.7
    • /
    • pp.16-22
    • /
    • 1995
  • Electrically-short wire antennas, widely used for mobile communications and EMI measurements, have low rediation efficiency and gain due to the ohmic loss predominant over the radiation power. A very short dipole antenna for wideband EMI measurements has been analyzed using the Method of Moments with the incorporatio of the ohmic loss calculated by the Phenomenological Loss Equivalennce Method(PEM). The calculated results show the rediation gain and efficiency very with the ohmic loss in a wide range of frequencies. Thses results can be effectively used for optimum design of very small antennas and probes for mobile communications and non-disturbing EMI measurements.

  • PDF

Analysis of Dielectric Coated Electromagnetically Coupled Coaxial Dipole Array (ECCDA) Antenna (유전체가 입혀진 전자기 결합 동축 다이폴 어레이 안테나의 해석)

  • Koo Sung-Mo;Yiug Woo-Suk;Lee Chang-Won
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.5 no.4
    • /
    • pp.317-324
    • /
    • 2004
  • Electromagnetically coupled coaxial dipole (ECCD) array antenna with and without short-ended termination is investigated theoretically. The integral equations are derived for the structure by use of the Fourier transform and mode expansion of radial waveguide. The integrals appearing in the integral equations are evaluated along the branch cut instead of real axis for a faster convergent integral. The effects of slots and dipoles, short-ended termination length, and dielectric coating on the radiation characteristics are presented. Radiation pattern of the structure is also investigated. The results of the present method are compared with those of the commercial EM simulator and good agreement is found.

  • PDF

Basic Aspects of Shear Wave Measurement in a Borehole

  • Kitsunezaki, Choro
    • The Journal of Engineering Geology
    • /
    • v.10 no.1
    • /
    • pp.63-77
    • /
    • 2000
  • The dipole method is now popular means for S-wave logging. Essential features of this method are explained, emphasizing basic concept based on approximation of the long-wavelength and the far-field. History of my researches concerned is shortly reviewed as background to reach the idea of this method. Short wavelength behavior of the dipole method is simply reviewed. Methods to reject tube wave noise are commented.

  • PDF