• 한국정보전자통신기술학회논문지
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• 제2권2호
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• pp.63-68
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• 2009

We study on the transient response in non-uniform microstrip lines with optically controlled microwave pulses. The transient response of the microwave pulses in plasma layer has been evaluated by reflection function of dielectric microstrip lines. The variation of characteristic response in plasma layer with localized pulses has been evaluated analytically. Reflection the change of the reflection amplitude has been observed.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.111-115
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• 2009

We present a study on the reflection of optically controlled microwave pulses from non uniform plasma layers in semiconductors. The transient response of the microwave pulses in different plasma layers has been evaluated by means of the reflection function of dielectric microstrip lines. The lines were used with an open-ended termination containing an optically induced plasma region, which was illuminated by a light source. The reflection characteristics impedance resulting from the presence of plasma is evaluated by means of the equivalent transmission line model. We have analyzed the variation of the transient response in a 0.01 cm layer with a surface frequency in the region of 128 GHz. In the reflection the variation of the diffusion length $L_D$ is large compared with the absorption depth $1/{\alpha}_l$. The variation of the characteristic response of the plasma layer with differentially localized pulses has been evaluated analytically. The change of the reflection amplitude has been observed at depths of 0.1 cm, 0.01 cm and $0.1{\times}10^{-5}$ cm respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.460-463
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• 2003

We report the microwave reflection coefficient $S_{11}$ of copper(II)-phthalocyanine(CuPc) using a near-field microwave microscope(NSMM) in order to understand the intrinsic electromagnetic properties of organic materials. For a NSMM system, a high-quility microstip resonator coupled with a dielectric resonator was used. The reflection coefficient $S_{11}$ was changed by the preparation conditions of CuPc thin films. We compared the reflection coefficient with crystal phase, surface morphology, UV absorption spectra and x-ray diffraction results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.86.3-86
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• 2002

.Introduction . Microwave subsurface radar . Reflection Phase . Experimental. Conclusion

• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.350-356
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• 2005

We report the space charge and the surface potential of the interface between metal and copper(Ⅱ)-phthalocyanine(CuPc) thin films by measuring the microwave reflection coefficients S/sub 11/ of thin films using a near-field scanning microwave microscope(NSMM). CuPc thin films were prepared on Au and Al thin films using a thermal evaporation method. Two kinds of CuPc thin films were prepared by different substrate heating conditions; one was deposited on preheated substrate at 150。C and the other was annealed after deposition. The microwave reflection coefficients S/sub 11/ of CuPc thin films were changed by the dependence on grain alignment due to heat treatment conditions and depended on thickness of CuPc thin films. Electrical conductivity of interface between metal and organic CuPc was changed by the space charge of the interface. By comparing reflection coefficient S/sub 11/ we observed the electrical conductivity changes of CuPc thin films by the changes of surface potential and space charge at the interface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.641-646
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• 2004

We report the changes of the microwave reflection coefficients S$_{11}$ of copper(II)-phthalocyanine (CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand the phase transition of CuPc. For a NSMM system, a high-quality microstrip resonator coupled with a dielectric resonator was used. CuPc thin films were prepared on the pre-heated glass substrates using a thermal evaporation method. The reflection coefficients S$_{11}$ of CuPc thin films were changed by the dependence on the substrate pre-heating temperatures. By comparing reflection coefficient S$_{11}$ and crystal structures, we found the phase transition of CuPc thin films from $\alpha$-phase to $\beta$-phase at the substrate heating temperature 200 $^{\circ}C$./TEX>.

• 대한전자공학회논문지
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• 제26권12호
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• pp.1940-1946
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• 1989

A design method of lossy interstage networks for broadband microwave amplifiers is presented. A lossy interstage network is assumed as the combination of two lossless networks between which a lossy serial impedance or a lossy parallel admittance is inserted. For the circuit with two transistors and a lossy element, realizable ranges of gain and reflection coefficients are derived. And the relationships between gain and reflection coefficients are derived. Illustrative examples are presented by using the proposed method.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.250-260
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• 2015

Purpose: Dual cylindrical microwave chambers equipped with an ohmic heating tube were designed and fabricated to maximize the electric field strength for expeditious heat treatment of particulate foods. Methods: The efficacy of the combination heater was investigated by simulating the electric field distribution by using COMSOL Multiphysics software. Results: All components of the designed microwave heating unit were suitable for transmitting maximal microwave power to the load. The simulated electric field distribution implied that single-mode microwave heating would be sufficient for the steady generation of a highly localized heating zone in the cavity. During impedance matching, the calculated reflection coefficient ($S_{11}$) was small, possibly implying minimal power loss and wave reflection in the designed microwave heating chamber. Conclusions: This study demonstrates the possibility of concentrating the microwave power at the centerline for a single-frequency microwave, for thermal treatment of multiphase foods without attenuating the microwave power.

• Transactions on Electrical and Electronic Materials
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• 제10권2호
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• pp.53-57
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• 2009

In this paper we develop a method to observe faults in semiconductor devices and transmission lines by calculating the variation of the reflection function in a dielectric microstrip line that has an open-ended termination containing an optically induced plasma region. It is analyzed with the assumption that the plasma is distributed homogeneously in laser illumination. With the non linear material of degradation, the concentration of the carrier in the part of the material has changed. Since the input wave has produced the phenomenon of reflection, the input signal to the open-ended microstrip lines can be observed on reflection to identify the location of the fault. The characteristic impedances resulting from the presence of plasma are evaluated by the transmission line model. The variation of the reflection wave in the microwave system has been calculated by using an equivalent circuit model. The transient response has been also evaluated theoretically for changing the phase of the variation in the reflection. The variation of characteristic response in differentially localized has been also evaluated analytically.