• Title, Summary, Keyword: narrow slit

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Equivalent Admittance of a Slit Fed by a Flanged Parallel-Plate Waveguide and Maximum Coupling Mechanism through a Narrow Slit (플랜지된 평행평판도파관으로 급전된 슬릿의 등가 어드미턴스 및 좁은 슬릿을 통한 최대결합 메커니즘)

  • 이종익;김강욱;조영기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.11
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    • pp.1116-1122
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    • 2004
  • The problem of electromagnetic coupling through a slit in a flanged parallel-plate waveguide is considered. The equivalent slit admittance associated with reactive powers near the coupling slit inside and outside the waveguide has been obtained. The maximum coupling mechanism for the case of narrow slit has been quantitatively discussed. The effects of various geometrical parameters such as guide height, slit width, and slit of offset on the radiation characteristics of the geometry have been investigated.

Maximum Electromagnetic Transmission through a Narrow Slit in Conducting Screen (도체 스크린의 좁은 슬릿을 통한 전자파 최대 투과 현상)

  • Lee, Jong-Ig;Cho, Young-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.8
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    • pp.832-836
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    • 2008
  • In this study, the electromagnetic coupling problem through narrow slit in an infinite conducting screen is considered for the case that the TM polarized plane wave is incident upon the slit. This study aims at explaining the mechanism of the maximum power transmission via the resonated slit using the equivalent circuit. It is shown that the transmitted power through the slit for the case of resonance corresponds to the power normally incident upon the conducting plane of the effective width 1/pi wavelengths, irrespective of the slit width. Some similarities between the maximum power transmissions observed in both the proposed structure and narrow slit in thick conducting screen are described from the viewpoint of equivalent circuit. In addition, it is found that, when the slit is resonated, the transmitted power equal to the scattered power.

Equivalent Admittance and Complex Powers in a Coupling through a Narrow Slit in a Parallel-Plate Waveguide (평행평판도파관의 좁은 슬릿을 통한 결합에 있어서 등가어드미턴스 및 복소전력)

  • Lee, Jong-Ig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.10
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    • pp.2059-2065
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    • 2009
  • In this study, it has been considered that the TEM wave is incident on the transverse slit in the upper plate of a short-ended parallel-plate waveguide (PPW). An equivalent slit admittance and complex power for the case of narrow slit are obtained. The conditions for the slit voltage and the complex power in case of the maximum coupling through the slit with a nearby scatterer exterior the PPW are checked.

Resonant Transmission through Slits in a Cavity inside a Thin Conducting Plane

  • Lee, Jong-Ig;Cho, Young-Ki
    • Journal of electromagnetic engineering and science
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    • v.10 no.3
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    • pp.127-131
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    • 2010
  • In this paper, the problem of electromagnetic transmission via slits in a cavity inside a conducting screen of finite thickness has been considered in the case that the transverse electric(to the slit axis) polarized plane wave is incident on a slit. The problem is solved numerically by the method of moments and the results are compared with those obtained from an equivalent circuit suitable for a case in which the slit width is infinite and the structure is modified to the two partially overlapped conducting planes. It is observed that when the cavity is resonated, the effective slit width reaches its maximum value of $1/\pi$ wavelengths, irrespective of the actual slit width and the incidence angle. When the thickness of the conducting plane is much smaller than the wavelength, the numerical results for the effective slit width(or transmission width) agree well with those obtained from the equivalent circuit, even though the slit is as narrow as the thickness of the conducting plane.

LONG-SLIT SPECTROSCOPY FOR EXTENDED OBJECTS (면천체(EXTENDED OBJECTS)에 대한 긴 슬릿 분광관측 연구)

  • SUNG EON-CHANG
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc1
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    • pp.39-60
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    • 2000
  • We will discuss two-dimmensional spectrophotometry including long-slit spectroscopy and narrow-band imaging. The basic principles, applications, and techniques of observations and data reduction of spectroscopy and spectrophotometry for extended objects are described. This discussion will focus on practical long-slit spectroscopy using a Cassegrain spectrograph attached with 2 or 4m class telescopes and on imaging spectrophotometry using narrow-band interference filter sets. We will discuss scientific applications.

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Electromagnetic Resonant Transmission through Slits in a Cavity inside Conducting Screen of Finite Thickness (두께가 유한한 도체 스크린 내부 캐비티의 슬릿을 통한 전자파 공진 투과)

  • Lee, Jong-Ig;Cho, Young-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.10
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    • pp.1094-1102
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    • 2010
  • In this paper, the problem of electromagnetic transmission via slits in a cavity inside conducting screen of finite thickness is considered for the case that the TE(to the slit axis) polarized plane wave is incident on the slit in conducting screen. Using the method of moments the variations of the transmitted power through the slits are obtained and compared with those computed from an equivalent circuit constructed using an equivalent slit admittance. It is found that the effective slit width of a narrow slit, at resonance, becomes $1/{\pi}$ wavelengths independently of the actual slit width. The transmission resonance phenomena in the proposed geometry are explained in connection with the variations of an equivalent admittance of the slit in the cavity.

Cavity-type and Parasitic-type Couplings through a Harrow Slit in A Parallel-Plate Waveguide with a Conducting Strip (평행평판도파관의 좁은 슬릿을 통한 도체 스트립과의 캐비티형 결합과 기생형 결합)

  • 이종익;고지환;조영기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.4
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    • pp.384-392
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    • 2003
  • In this study, the electromagnetic coupling through a narrow transverse slit in the upper wall of a parallel-plate waveguide(PPW) covered by a dielectric slab with a nearby conducting strip on the slab is considered. Two contrastive coupling phenomena, cavity-type and parasitic-type, observed in the geometry have been distinguished by differences in the resonant strip lengths and offset positions, induced strip current, radiation pattern, frequency bandwidth, and electromagnetic field distributions near the coupling slit.

A Breaching of Electromagnetic Shielding by Narrow Aperture in Metal Film

  • Park, Doo Jae;Chu, Hong;Kyoung, Jisoo;Choi, Soo Bong
    • Journal of the Optical Society of Korea
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    • v.20 no.5
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    • pp.563-566
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    • 2016
  • We report a theoretical research for the condition of electromagnetic shield breaching when a narrow aperture is punctured in thin metal film. To calculate electromagnetic field transmission through a narrow slit, a Rayleigh wave expansion has been applied for free standing, thin metal film. We found that the DC electric field allows perfect transmission when the length of the slit is infinite, regardless of the other geometrical factors such as slitwidth and thickness. Slitwidth dependent transmission spectra as a function of frequency shows a cutoff frequency that decreases almost linearly to the slitwidth, giving that almost successful shielding is only possible when the slitwidth is smaller than 1 micron.

Coupling through a narrow slit in a parallel-plate waveguide covered by a dielectric slab with a conducting strip on the slab (유전체 슬랩으로 덮힌 평행평판 도파관의 좁은 슬릿을 통한 슬랩 위의 도체 스트립과의 결합)

  • Lee, Jong-Ik;Hong, Jae-Pyo;Jo, Yeong-Gi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.2
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    • pp.68-74
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    • 2000
  • The problem of electromagnetic coupling through a narrow slit in a parallel-plate waveguide(PPW) covered by a dielectric slab with a conducting strip on the slab is considered for the case that the TEM wave is incident in the PPW. Coupled integral equations for the tangential electric field in the slit and the induced current over the strip are derived and solved numerically by use of the method of moments. In order to show the effect of the conducting strip on the coupling, some numerical results for the reflected and transmitted powers in the guide, the coupled power through the slit, the equivalent slit admittance, and radiation pattern are presented. From the results, it is observed that the maximum available power coupled through the slit exterior to the PPW amounts upto 50% of the incident power in the PPW.

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Electromagnetic Transmission through Slits in Two Adjacent Conducting Parallel-Plates (근접하는 도체 평행 평판의 슬릿을 통한 전자파 투과)

  • Lee, Jong-Ig;Ko, Ji-Hwan;Cho, Young-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.1
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    • pp.83-90
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    • 2009
  • In this paper, the problem of electromagnetic transmission through slits in two parallel conducting plates which separate two half spaces is considered. The coupled integral equations for the electric field distributions over the slits are developed for the case that the TM polarized plane wave is incident on the slit and solved by the method of moments. The transmitted power beyond the slit-perforated conducting parallel plates is computed in order to check the variations of the coupled power through slits against some parameters such as the incident angle of the TM polarized wave, slit width, lateral distance between two slits, and distance between the conducting plates. When the lateral distance between two slits approaches near the multiples of half wavelengths, the transmission resonance (maximum power transmission) is observed. If the slit width in the incident side is narrow and the distance between conducting plates is small compared to the wavelength, the maximum of transmitted power is observed to be nearly independent of the incident angle and slit width. In addition, the mechanism of the transmission resonance in the present geometry is explained using a simplified geometry and its equivalent circuit.