• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.9
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• pp.21-27
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• 1997

Square spiral inductors are designed with EM program in accordance with the inner diameter and the metal thickness which is 0.2.mu.m and 20.mu.m respectively. We propose a parameter extraction method based on the S-parameter. Lumped equivalent circuits of spiral inductors are analyed with reflection coefficient S$_{11}$, of witch freqency rnage is 1~10GHz. When metal thickness is 0.2.mu.m, S$_{11}$ with EM simulation is not the same as S$_{11}$ that of SPICE simulation. So we suggests a new lumped equivalent circuits which compensate circuits. Te new lumped equivalent circuits are adequate for other inductor with small scale at high frequencies.ncies.

• 전자공학회논문지 IE
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• v.49 no.2
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• pp.18-23
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• 2012

A method to determine the equivalent circuits of broadband ultrasound transducers is necessary for designing filters that match the impedances of the transducer and the analysis of the transducer. A method is proposed to determine the equivalent circuits of broadband transducers with 2 resonances in the frequency band of interest. The circuit parameters are estimated by iterative Levy method with the measured electrical conductance data. The method is illustrated by computing the conductance and susceptance of the equivalent circuits of 3 types of broadband transducers. The equivalent circuit of a transducer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.515-521
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• 2013

Magnetoelectric(ME) bulk composites with PZT-PNN-PZN/$Fe_2O_4$ were prepared by using a conventional ceramic methods and investigated on the ME voltage vs frequency of ac magnetic fields. We made the electric equivalent circuits by using the Maxwell-Wagner model and simulated the frequency dependence of ME voltage in low frequency region. ME devices were described by a series of two equivalent circuits of piezoelectric and magnetic, which have the relaxation time ${\tau}$ due to the interaction between ME device and load resistor. Equivalent circuit of piezoelectric material is independent of frequency. However ferrite magnetic materials have Debye absorption and dipolar dispersion, whose equivalent circuit is a function of frequency. Therefore we suggest the resistance in the equivalent circuit is proportion to $1+{\omega}^2{\tau}^2$ and the capacitance is in inverse proportion to $1+{\omega}^2{\tau}^2$ in the magnetic materials.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.70-73
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• 2002

High frequency digital LSI circuits are usually composed of many sub-circuits coupled with interconnects. They sometimes causes serious problems of the fault switching by time-delays, crosstalks, reflections of signals and so on. Therefore, it is very important to develop a user-friendly simulator for solving these problems. Although a moment matching method is widely used as the reduction technique of interconnects, it may happen to arise erroneous results for evaluating the poles far from the origin. In this paper, we show an asymptotic method in the complex frequency-domain, where we calculate the exact poles and residues giving large effect to the transient responses. Then, the interconnects are replaced by the asymptotic equivalent circuits using the poles and residues. Thus, we can develop a users-friendly simulator using the equivalent circuits.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.45-49
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• 1998

In this paper, the direct thrust control of PWM Inverter-fed Single-sided Linear Induction Motor (hereinafter referred to as "SLIM") is achieved with Space Vector control and PI control. The trembling of air gap length which is occured between the primary winding core and the secondaty structure of the SLIM must be minimized in order to get quick response characteristic. First, voltage equations of SLIM are shown on the suitable d-q axis equivalent circuits which analyze characteristics of the thrust and the normal force. Also, modeling and analysis of the d-q axis equivalent circuits are able to make robust transient thrust from the current regulation in the equivalent circuits. These results exemplified the direct drive of SLIM with the reference speed and thrust were verified by the experiments.periments.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.577-582
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• 2004

In this paper, lumped equivalent circuits for a conventional parallel directional coupler are proposed. This equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of parallel-coupled line. By using the derived design formula, we have designed the 3dB and 4.7dB MMIC couplers at the center frequency of 3.4GHz and 5.6GHz respectively. Measurements for the designed MMIC directional couplers show at 4dB and 5.2dB-coupling value at the center frequency of 3.4GHz and 5.6GHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.368-374
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• 2002

In this paper, we introduce a procedure to obtain a equivalent circuit of comb-line band pass filter. By employing equivalent circuits of each asymmetrical coupled line. we composed the full equivalent circuit of comb-line bandpass filter and derived simple design equations for extracting each line's impedance. To show the validity of design equations, we simulated and fabricated a planar type comb-line bandpass filter, which has center frequency 1.8㎓, band-width 50㎒ and four resonators. The resulting filter is very compact, have broad stop band with the second pass band centered at four times the center frequency of the first pass band. The experimental results show exact performances of design specification.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.353-356
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• 2000

Multi-bias parameter extraction technique for HEMT small signa] equivalent circuits is presented in this paper. The technique in this paper uses S-parameters measured at various bias points in the active region to construct one optimization problem, of which the vector of unknowns contains only a set of bias-independent elements. Tests are peformed on measured S-parameters of a pHEMT at 30 bias points. Results indicate that the calculated S-parameters is similar to the measured data.

• Journal of electromagnetic engineering and science
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• v.13 no.1
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• pp.54-61
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• 2013

An equivalent model has been developed to estimate the electromagnetic immunity for integrated circuits under a complex electromagnetic environment. The complete model is based on the characteristics of the equipment and physical configuration of the device under test (DUT) and describes the measurement setup as well as the target integrated circuits under test, the corresponding package, and a specially designed printed circuit board. The advantage of the proposed model is that it can be applied to a SPICE-like simulator and the immunity of the integrated circuits can be easily achieved without costly and time-consuming measurements. After simulation, measurements were performed to verify the accuracy of the equivalent model for immunity prediction. The improvement of measurement accuracy due to the added effect of a bi-directional coupler in the test setup is also addressed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.3 no.2
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• pp.10-17
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• 1966

A method by which solutions of the differential equations of any other distributed circuits can be obtained is described when the solution of the differential equation of an R-C distributed amplifier is known. A graphical method of transforming any R-C ditributed circuit into an equivalent circuit which has a constant R(x)$cdot$C(x) was also obtained. The theoretical verification of this method is possible. For simplicity, any R-C distributed circuit can be transformed into an equivalent circuit which is a distributed circuit of either constant R(x) or C(x). Using this equivalent circuit and considering a lumped circuit, an approximate analysis and synthesis can be made simply.