• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.7
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• pp.76-81
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• 2011

A new via cutting structure in 2-layer DRAM package substrate has been fabricated to lower its power distribution network(PDN) impedance. In new structure, part of the via is cut off vertically and its remaining part is designed to connect directly with the bonding pad on the package substrate. These via structure and substrate design not only provide high routing density but also improve the PDN impedance by shortening effectively the path from bonding pad to VSSQ plane. An additional process is not necessary to fabricate the via cutting structure because its structure is completed at the same time during a process of window area formation. Also, burr occurrence is minimized by filling the via-hole inside with a solder resist. 3-dimensional electromagnetic field simulation and S-parameter measurement are carried out in order to validate the effects of via cutting structure and VDDQ/VSSQ placement on the PDN impedance. New DRAM package substrate has a superior PDN impedance with a wide frequency range. This result shows that via cutting structure and power/ground placement are effective in reducing the PDN impedance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.73-81
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• 2011

As high speed digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information, it can bring about many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge to implement a system. Especially, the noise sources in high frequency digital systems include the noise in power supply, ground and packaging, and they destroy the fidelity of signals. Therefore PCB design with impendence matching is needed to improve fidelity of signal in H/W. In this paper, we have developed an impedance control and analysis tool for multi-layer PCB design, and simulates the tracks controlled impedance with the test coupon. So, it can save the design time and support the economical PCB design.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.1-7
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• 2011

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.1-8
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• 1999

A complete electromagnetic simulation for a ground-penetrating radar(GPR) is implemented by employing 3-dimensional dispersive finite-difference time-domain(FDTD) method. The presented simulation model includes the cavity-backed bow-tie antennas, which are terminated by resistors. And an equivalent cirvuit consisting of the input impedance of the antenna and the characteristic impedance of the feed line is used to calculate the response in the receiving antenna. Actual emasurements of a GPR system including our manufactured bow-tie antenna pair are performed just above dry sand contained in a PVC tank. It is confirmed that the FDTD simulation results agree well with the actual measurement data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.2
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• pp.188-193
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• 2010

In this paper, SI(Signal Integrity) characteristic of the 4-layer PCB(Printed Circuit Boards) with a through-hole via was analyzed by impedance mismatching between the through-hole via and the transmission line, and deterioration of clock pulse response characteristic due to the P/G plane resonances which are generated between the power and the ground plane. The minimized impedance mismatching between the through-hole via and the transmission line for the improving of SI characteristic is confirmed by the TDR(Time Domain Reflector) simulation and lumped element modeling of the through-hole via. And the cancellation method of P/G plane resonances for improvement of the SI characteristic is represented by simulation result.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.964-973
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• 2008

In this study, a short-wavelength coplanar-type transmission line employing periodic ground structure (PGS) was developed for application to miniaturized on-chip passive component on Si Radio Frequency Integrated Circuit (RFIC). The transmission line employing PGS showed shorter wavelength and lower characteristic impedance than conventional coplanar-type transmission line. The wavelength of the transmission line employing PGS structure was 57 % of the conventional coplanar-type transmission line on Si substrate. Using the theoretical analysis. basic characteristics of the transmission line employing PGS (e.g., bandwidth. loss, impedance, and resonance characteristics) were also investigated in order to evaluate its suitability for application to a development of miniaturized passive on-chip components on silicon RFIC. According to the results. the bandwidth of the transmission line employing PGS was more than 895 GHz as long as T is less than 20${\mu}m$, and the resonance characteristic was observed in 1239 GHz, which indicates that the PPGM structure is a promising candidate for application to a development of miniaturized on-chip passive components on Si RFIC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.119-125
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• 2009

This paper deals with the characteristics of soil ionization affecting the dynamic performance of grounding systems under lightning impulse voltage. A concentric hemispherical electrode system was employed in order to facilitate the field calculation and analysis of the experimental results. The parameters such as the ionization threshold and breakdown field intensity, the pre-ionization and the post ionization resistances, the time-lag to ionization, the transient impedance, the equivalent ionized radius for various soil media were measured and analyzed. The dynamic characteristics of ionization processes under lightning impulse voltage are strongly dependent on the types of soil and water content. As a result, a soil ionization reduces the ground resistance and there is a little effect of applied impulse polarity on the soil ionization threshold field intensity. Although the ionization threshold field intensity of wet clay with 30% water content is the highest, its ionized zone was found to be the smallest amongst the test samples.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.114-121
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• 2010

This paper deals with the frequency-dependent grounding impedances of counterpoises relevant to the soil resistivity, the length of counterpoises and the feeding point of test current. The grounding impedances of counterpoises buried in one-layered and two-layered soils were measured and analyzed in the frequency range from 1[kHz] to 10[MHz]. As a result, the frequency-dependent grounding impedances strongly depend on the soil resistivity, and the grounding impedances within the frequency of several tens [kHz] are capacitive behavior in high soil resistivity. When injecting the ground current to the end of counterpoise buried in soil with high resistivity, the grounding impedances in high frequency are increased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.55-56
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• 2017

In this paper, a wideband loop antenna is designed using a CPW feeding method for indoor digital TV applications. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.601-608
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• 2016

The electrical characteristics of the soil where a ground electrode is buried vary with regions, seasons and environmental factors. Electrical discharge in the vicinity of the ground electrode will occur differently and significantly affect the performance of the grounding system. It is necessary to analyze discharge and ionization characteristics of soils when the grounding system is designed. The aims of this investigation are to understand correlation between the soil ionization and the transient ground impedance. This paper presents the experimental results on the soil ionization parameters and the transient ground resistance due to the soil ionization around a hemispherical ground electrode stressed by lightning impulse voltages.