• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.236-240
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• 1988

The simplified equivalent by using the short circuit impedance has been used for analyzing the prospective transient recovery voltage of the large power system. But it sometimes generates untorelable error in the rate-of-rise of TRV when using the Thevenin equivalent source. This paper provides the new equivalent by using the multi-port theory. The application of the new method to the sample system gives satisfactory accuracy compared with the short-circuit equivalent.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.357-360
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• 2000

This paper describes a parameter extraction method for HBT(Heterojunction Bipolar Transistor) equivalent circuit model without measurements of special test structures or numerical optimizations. Instead, all equivalent circuit parameters are calculated analytically from small-signal S-parameters measured under different bias conditions. These values being extracted from the cutoff mode can be used to extract intrinsic parameters at the active mode. This method yields a deviation of about 1.3 % between the measured and modeled S-parameters.

• 산업기술연구
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• 제28권B호
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• pp.251-255
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• 2008

Metamaterial are artificial structures that can be designed to exhibit specific electromagnetic properties not commonly found in nature. Metamaterial transmission lines are usually fabricated with a microstrip structure and it's equivalent circuit is composed of two series capacitances and a shunt inductance. However microstrip structure need a via hall for realizing a shunt inductance. To eliminate via hall, we proposed a CRLH transmission line using a CPW structure, and obtained equivalent circuit values, line parameters.

• Journal of electromagnetic engineering and science
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• 제2권2호
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• pp.100-104
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• 2002

A proper equivalent circuit model for coupling iris has been derived in order to compensate the length of cavity in a $TE_{011}$TEX> mode cylindrical cavity filter. A method to resolve the difference in bandwidth and feature or ripple systematically has been proposed. This method can be applied to other types of waveguide cavity filter.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.849-854
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• 1998

The load characteristics on the voltage gain and efficiency were analyzed using a lumped constant equivalent circuit of the piezoelectric transformer. These analytical results were confirmed by experiments. Theoretical values of voltage gain were nearly constant with experimental ones. However, It was shown that theoretical values of efficiency is higher than experimental ones.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.122-127
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• 2011

A general analysis of an aperture-coupled vertically mounted strip antenna is presented to examine its circuit characteristics. Based on the present analysis, an equivalent circuit model is developed, and an analytic or semi-analytic evaluation of the related circuit element values is described. The effects of structure parameters on the antenna characteristics were studied with the developed equivalent circuit, and the design curves were obtained. To check the validity of the proposed analysis and design theory, two C-band antennas (5.0 GHz and 4.5 GHz) were designed and fabricated. Their computed characteristics, derived from the proposed network analysis, were compared with the measurement and simulation results. The error of the current model in predicting the operating center frequency was less than 0.50 %. In addition, the observed bandwidth was found to be comparable to the conventional microstrip antennas. All the results fully validated the efficiency and accuracy of the proposed analysis and network model.

• ETRI Journal
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• 제28권2호
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• pp.182-190
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• 2006

The circuit modeling of interdigitated capacitors fabricated by high-k low-temperature co-fired ceramic (LTCC) sheets was investigated. The s-parameters of each test structure were measured from 50 MHz to 10 GHz, and the modeling was performed using these measured sparameters up to the first resonant frequency. Each test structure was divided into appropriate building blocks. The equivalent circuit of each building block was composed based on the partial element equivalent circuit (PEEC) method. Modeling was executed to optimize the parameters in the equivalent circuit of each building block. The validity of the extracted parameters was verified by the predictive modeling for the test structures with different geometry. After that, Monte Carlo analysis and sensitivity analysis were performed based on the extracted parameters. The modeling methodology can allow a device designer to improve the yield and to save time and cost for the design and manufacturing of devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.253-256
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• 1991

Tie constructed the equivalent circuit of the magnetotransistor by the representation of the operating principle as two independent current sources. The equivalent circuit has been analyzed quantatively and the calculated values agreed to the experimental ones. It has been found out that the structure of MT inflenuces on the relative sensitivity and the structure parameters can be extracted from the equivalent circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.388-393
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• 1988

New circuit D-Q transformation concept is introduced to analyze AC converters such as inverters, rectifiers and cyclo-converters with ease. The equivalent linear time invariant circuit is obtained by substituting switches with equivalent turn-ratio variable transformers and changing balanced AC reactors into equivalent DC reactors combined by gyrators. This circuit enables us to utilize the powerful linear system analysis techniques such as Laplace transform otherwise which could not be applied to the time varying switching systems. Direct substitution of switches of DC converters with transformers is shown as a preliminary. Then the modeling procedure is shown for a controlled rectifier-inverter circuit. Finally an analysis example is proposed for a buck-boost inverter and the result is compared with the conventional approach. This approach is applicable to all AC converter families to determine the AC transfer functions and the DC operating points. It is identified that the switching systems are equivalent to the RLC filter circuits with transformers and gyrators.

• 전기의세계
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• 제22권1호
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• pp.42-51
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• 1973

The contriving equivalent circuit of single phase induction motor which does not separate the primary leakage reactance and the secondary leakage reactance by the revolving field theory, and the graphically calculating method of the characteristics with T-type circle diagram of three phase induction motor which does not suppose the primary leakage reactance can be drawn up only by the no load test, the lock test, and measuring the resistance of stator winding are suggested in this paper. The method which can calculate the parameters of the equivalent circuit and the characteristics with no load test, lock test and measuring resistance of stator windings is suggested in this paper. Considered the exciting current in lock test, we could calculate very accurate characteristics of the single phase induction motor.