• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.31-39
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• 2004

This paper illustrates the noise characteristics under chip's core operations according to types of packages and modules for DDR DRAM For analyzing this, the impedance profiles and power noises are analyzed with DRAM chips having commercial TSOP package and commercial FBGA package on TSOP-based DIMM and FBGA-based DIMH In controversy with common concepts, we find that the noise-isolation characteristics of FBGA package are more weak and sensitive on transferred noises than those of the TSOP package. In addition, the simulated results show that the decoupling capacitor locations of modules are more important to control the self and transfer noise characteristics than the lead inductance of the packages. Therefore, satisfying the target spec of the noise suppression and isolation can be achieved through the design of power distribution systems only with considering not only the package types but also the whole module system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.1-6
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• 2007

In this paper, the spiral zeroth-order resonance (ZOR) antenna using composite right- and left-handed (CRLH) transmission line is proposed. The zeroth-order resonant characteristics of the antenna are described by dispersion relation of a periodic structure. The size of the $2{\times}2$ spiral ZOR antenna is $0.155{\lambda}_{0}{\times}0.155{\lambda}_{0}$. By increasing shunt inductance of CRLH transmission line, the size of this antenna is reduced by 65% compared with that of a mushroom ZOR antenna. The radiation pattern of this antenna have omnidirectional pattern which is similar to that of mushroom ZOR antenna.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.45-54
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• 2004

Microwave characteristics of ridge type CPW traveling-wave(TW) electroabsorption modulator and photodetector are affected by the thickness of intrinsic layer, width of guiding layer, and the separation of signal and ground electrodes. These factors are determined effective index of microwave and characteristic impedance due to changing of capacitance(C) and inductance(L) of device. However, conventional equivalent circuit of TW-structure is approximated to microstrip and CPW transmission line by distribution of electric and magnetic fields, respectively. In this paper, we analyzed microwave characteristics of TW-structure and found more accurate value of C and L by using finite difference time domain (FDTD) method. These values are adopted circuit element of equivalent circuit. Microwave characteristics obtained by the FDTD and equivalent circuit model show good agreement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.72-77
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• 2006

This paper presents the transient impedance behaviors according to the length of down conductors of grounding systems to lightning impulse currents. The potential rise and effective impulse ground impedance of the deeply-driven ground rod and grounding grid subjected to the impulse currents were measured and analyzed as a function of the rise time of impulse currents and lengths of down conductor. The transient ground impedances strongly depend on the configuration and size of grounding electrodes, the waveform of impulse currents and the length of down conductors, and the installation methods reducing the inductance of down conductors are an important factor to decrease the transient ground impedances.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1745-1752
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• 2009

This Paper represents a new method, which uses defected ground structure (DGS) on the ground planes of microstrip lines, to reduce the size of the Schiffman phase shifter. DGS on the microstrip line shows an increased slow-wave effect due to the additional equivalent L and C components. So the electrical length of transmission line with DGS is longer than that of standard transmission line for the same physical length. Then, the length of transmission line with DGS can be shortened in order to maintain the original electrical length to be same. The performances of reduced phase shifter with DGS are quite similar to the ones of original Schiffman phase shifters. We can reduce the size about 15% using the DGS in original Schiffman phase shifter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.55-60
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• 2008

This paper proposed a dual-band RF switch using a Composite Right/Left Handed transmission line(CRLH TL) and PIN diode. RF switch is usually consist of $\lambda/4$ Right Handed transmission line(RH TL) and PIN diode. The dual band characteristics of RF switch was achieved by using CRLH transmission line instead of RH transmission line. CRLH Open-Stub was designed for resolve to reduction of isolation due to Package Inductance of PIN diode. The proposed RF switch was designed at GSM and DCS frequency-band. The measurement results showed a good agreement with theoretical result.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.62-65
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• 2003

We considered of the efficiency for the Buck+Half bridge converter This converter has advantages of applications for a low output voltage, a high output current and a wide input voltage. Developed the Buck converter ratings and the Half Bridge converter ratings are 36$\~$72V Input and 22V/5A output, 19$\~$24v input and 3.3V/30A output, respectively. Buck converter is operated with zero voltage switching process to reduce the switching losses. The 80.1 $\~$97.6$\%$ of the efficiency is measured at 18.4 $\mu$H output filter inductance of Buck convertor. In Half Bridge convertor, the 86$\~$96.4$\%$ of the efficiency is measured at 100kHz switching frequency with PQI core.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.16-21
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• 2005

In paper, propose new partial resonance ZCS PWM controlled High frequency insulating Full-bridge DC/DC converter not using exciting current of high frequency transformer. It is compared with the existing principles in characteristics. It also realizes a widely stabilized ZVS operating using new ON-OFF control method at synchronized power rectification MOSFET of high frequency insulating transformer secondary. Besides, it is brought over 97[%] measurement efficiency by proposed DC-DC converts. It is proved effectiveness of new methods using DC UPS PWM rectifier as switching power supply.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.887-893
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• 1999

The characteristics of ozone generator targeted for air or water sterilizing in the vessel utilizing the surface corona discharge between the electrodes on the ceramic substrate was investigated by using the frequency control method. The frequency control was achieved by controlling the degree of resonance between the secondary winding inductance of transformer and the electrode capacitance of ceramic discharge plate, and the range of control was found to be 5 times of discharge current. This frequency control method showed the efficiency of 28 mP ozone generation and the stability within 3.4 % when the input voltage was varied within 40% range. The frequency control method is regarded to be more efficient way of corona discharge control compared to the conventional on/off control or voltage control methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.65-70
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• 2006

This paper presents the transient behaviors of grounding system impedance against lightning impulse currents. The dynamic characteristics of the deeply driven ground rod and grounding grid subjected to the impulse current were investigated. The transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient ground impedance of grounding system Also, the deeply-driven ground rod was effective to reduce the transient ground impedance in time domain of miceroseconds.