• Title, Summary, Keyword: equivalent admittance

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Equivalent System Using Driving-Point Admittance Function (구동점 어드미턴스 함수를 이용한 등가 시스템)

  • Hong, Jun-Hee;Jeong, Byung-Tae;Cho, Kyung-Rae;Jeong, Hae-Seong;Park, Jong-Keun
    • Proceedings of the KIEE Conference
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    • pp.75-77
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    • 1994
  • This paper presents a method of obtaining transmission network equivalents from the network's driving-point admittance characteristic. Proposed method is based on modal decomposition representation for the large-scale interconnected system. As a result, Norton-type of discrete-time filter model can be generated. It can reproduce the driving-point admittance characteristic of the network. Furthermore proposed model can be implemented into the EMTP in a direct manner. The simulation results with the full system representation and the developed equivalent system showed a good agreement.

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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.

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.

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.

Radiation Admittance Calculation of the Rectangular Microstrip Antenna (구형 마이크로스트립 안테나의 복사어드미턴스 계산)

  • Hong, Jae-Pyo;Cho, Young-Ki;Son, Hyon
    • Proceedings of the KIEE Conference
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    • pp.430-432
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    • 1988
  • Radiation admittance of the rectangular microstrip antenna is calculated by using equivalent ${\pi}$-network parameters of the slit in the wall of the parallel plate waveguide filled with homogeneous dielectric. Using equivalent transmission line model, return loss is calculated and compared with experimental result. Calculated values for the return loss show good agreement with experimental values.

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Improved Method for Calculating Radiation Admittance of a Rectangular Microstrip Patch Antenna (구형 마이크로스트립 안테나의 개선된 복사 어드미턴스 계산방법)

  • Hong, Jae-Pyo;Cho, Young-Ki;Son, Hyon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.2
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    • pp.35-40
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    • 1989
  • In this paper, a new method which simultaneously gives the radiation conductance and susceptance of the rectangular microstrip patch antenna. This solution is derived from the load admittance of the equivalent ${\pi}-$network circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Our theoretical results for the radiation admittance are compared with other theoretical results. Also, our theoretical return loss and resonant frequency which are calculated by use of the equivalent transmission line model are in fairly good agreement with the experimental results.

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Grain Size Dependence of Ionic Conductivity of Polycrystalline Doped Ceria

  • Hong, Seong-Jae
    • The Korean Journal of Ceramics
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    • v.4 no.2
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    • pp.122-127
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    • 1998
  • Conductivities of polycrystalline ceria doped with several rare earth oxides were measured by AC admittance and DC four probe method. The conductions were separated into grain and grain boundary contributions using the complex admittance technique as well as grain size dependence of conductivity. The grain size dependence of polycrystalline conductivity, which can be adequately described by the so-called brick layer model, appears to give a more reliable measure of the grain conductivity compared to the complex admittance method. Polycrystalline resistivity(1/conductivity) increases linearly with the reciprocal of grain size. The intercept of resistivity vs. inverse grain size plot gives a measure of the grain resistivity and the slope gives a measure of the grain boundary resistivity. It was also noted that errors involved in the analysis of experimental data may be different between the complex admittance method and the impedance method. A greater resolution of the spectra was found in the complex admittance method, insofar as the present work is concerned, suggesting that the commonly used equivalent circuit may require re-evaluation.

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Mechanism Analysis and Stabilization of Three-Phase Grid-Inverter Systems Considering Frequency Coupling

  • Wang, Guoning;Du, Xiong;Shi, Ying;Tai, Heng-Ming;Ji, Yongliang
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.853-862
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    • 2018
  • Frequency coupling in the phase domain is a recently reported phenomenon for phase locked loop (PLL) based three-phase grid-inverter systems. This paper investigates the mechanism and stabilization method for the frequency coupling to the stability of grid-inverter systems. Self and accompanying admittance models are employed to represent the frequency coupling characteristics of the inverter, and a small signal equivalent circuit of a grid-inverter system is set up to reveal the mechanism of the frequency coupling to the system stability. The analysis reveals that the equivalent inverter admittance is changed due to the frequency coupling of the inverter, and the system stability is affected. In the end, retuning the bandwidth of the phase locked loop is presented to stabilize the three-phase grid-inverter system. Experimental results are given to verify the analysis and the stabilization scheme.

Impedance spectroscopy analysis of polymer light emitting diodes with the LiF buffer layer at the cathode/organic interface (LiF 음극 버퍼층을 사용한 폴리머의 효율 향상에 관한 임피던스 분석)

  • Kim, H.M.;Jang, K.S.;Yi, J.;Sohn, Sun-Young;Park, Kuen-Hee;Jung, Dong-Geun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.277-278
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    • 2005
  • Admittance Spectroscopic analysis was applied to study the effect of LiF buffer layer and to model the equivalent circuit for poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV)-based polymer light emitting diodes (PLEDs) with the LiF cathode buffer layer. The single layer device with ITO/MEH-PPV/Al structure can be modeled as a simple parallel combination of resistor and capacitor. Insertion of a LiF layer at the Al/MEH-PPV interface shifts the highest occupied molecular orbital level and the vacuum level of the MEH-PPV layer as a result the barrier height for electron injection at the Al/MEH-PPV interface is reduced. The admittance spectroscopy measurement of the devices with the LiF cathode buffer layer shows reduction in contact resistance ($R_c$), parallel resistance ($R_p$) and increment in parallel capacitance ($C_p$).

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Stability Analysis of Nonlinear Pulse-Modulated System Subject to Gaussian Noise (가우스 잡음을 고려한 비선형 펄스 변조 시스템의 안정도 분석)

  • 강영채
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.19 no.6
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    • pp.67-79
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    • 1982
  • The stability of general pulse-width modulation system with Gaussian random disturbance was discussed . General system is divided into nonlinear and linear elements using the conventional describing function method. The concept of the equivalent admittance was used to find the transfer characteristic of the nonlinear element of the system. In this paper the self-sustained oscillation condition in the autonomous system was derived and the results was analyzed with computer simulation.

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