• Proceedings of the KIEE Conference
• /
• 2007.11b
• /
• pp.37-39
• /
• 2007

In the faults of power line, single line ground and line-to-line fault make power system to unbalanced. These fault currents make unbalanced power system. This paper suggests the simulation results of dynamic characteristic of HTS cable system under unbalanced faults condition using EMTDC, Quench phenomenon and current limiting effects are observed. However, quench on the HTS is destroy cable system, coordination with SFCL has to be considered.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.7 no.4
• /
• pp.1-5
• /
• 1970

This presents the way in shich the input impedance, and the output waveform of the line discriminator are influenced by a discrepancy of less than $\pm$10% in the coupling resistor resistance from the optium value(Characteristic impedance of the transmission line used in the line discriminator)

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.8
• /
• pp.1248-1256
• /
• 2008

In this paper, basic characteristics of transmission line employing PPGM (periodically perforated ground metal) were investigated using theoretical and experimental analysis.According to the results, unlike the conventional PBG (photonic band gap) structures, the characteristic impedance of the transmission line employing PPGM structure showed a real value, which exhibited a very small dependency on frequency. The transmission line employing PPGM structure showed a loss (per quarter wave length) higher by $0.1{\sim}0.2\;dB$ than the conventional microstrip line. According to the investigation of the dependency of RF characteristic on ground condition, the RF characteristic of the transmission line employing PPGM structure was hardly affected by the ground condition in the frequency lower than Ku band, but fairly affected in the frequency higher than Ku band, which indicated that coplanar waveguide employing PPGM structure was optimal for RF characteristic and reduction of size. Considering above results, impedance transformer was developed using coplanar waveguide with PPGM structure for the first time, and good RF characteristics were observed from the impedance transformer. In case that {\lambda}/4$ impedance transformer with a center frequency of 9 GHz was fabricated for a impedance transformation from 20 to10 {\Omega}$, the line width and length were 20 and $500\;{\mu}m$, respectively, and its size was only 0.64 % of the impedance transformer fabricated with conventional microstrip lines. Above results indicate that the transmission line employing PPGM is a promising candidate for a development of matching and passive elements on MMIC.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.2
• /
• pp.165-172
• /
• 2019

Using two or more coaxial lines, if one port is connected in series and the other port is connected in parallel, it can be implemented the wideband transmission line transformer(TLT). Because the wideband TLT utilizes the outer conductor of the coaxial line, it is difficult to predict the characteristics. In this paper, based on the analysis for the transfer characteristic(S21) according to the loss of the each line in ${\lambda}/4$-microstrip line TLT, the operating characteristic of the fabricated wideband 4:1 TLT using two $25{\Omega}$-coaxial lines is investigated. The fabricated wideband TLT shows the notch characteristic in which the transfer signal sharply decreases at ${\lambda}/4$ frequency of the coaxial line and has a value within -0.2dB of the transfer characteristic(S21) in $0.06{\sim}0.2{\lambda}$ frequency range of the coaxial line. This transfer characteristics(S21) can change the operating frequency range slightly and set the optimum transfer characteristic(S21) at the desired frequency by changing the length of the microstrip line.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.4 no.2
• /
• pp.122-129
• /
• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Proceedings of the KOSOMBE Conference
• /
• v.1993 no.11
• /
• pp.13-16
• /
• 1993

In this paper the morphological characteristic parameters according to the Lee's physical constitution theory are suggested using the X-ray computed tomography. The Lee's physical constitution theory is classify into 4 physical constitutional types by the relative degree of visceral function: those are macro-negative(strong liver- weak lung), micro-negative(strong kidney- weak spleen), micro-positive(strong spleen- weak kidney) and macro-positive(string lung- weak liver). The morphological characteristic parameters are the following. The AA-line is the distance between Rt. & Lt. acupuncture point keug-cheun. The BB-line is the length of lung. The CC-line is the longest width of thorax. The DD-line is the vertical distance between the CC-line and the EE-line. The EE-line is the distance between the Rt. and Lt. anterior superior iliac spines. As the results macro-negative(strong liver-weak lung) has the longest CC-line and the short BB-line. Micro-negative(strong kidney-weak spleen) has the longest EE-line and the short CC-line. Micro-positive(strong spleen-weak kidney) has the longest DD-line and the short BB-line. And macro-positive(strong lung-weak kidney) has the longest BB-line and the short EE-line.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.4
• /
• pp.699-704
• /
• 2007

In this paper, optimized model was designed for the starting characteristic of the Single-Phase Line-Start Permanent Magnet Synchronous Motor by using the Design of Experiment. A field pole angle, thickness and distance from center axis of permanent magnet were selected as design factor. We executed the transient state characteristic analysis of 8 test models. The transient state characteristic analysis was executed by using the 2 dimensional Finite Element Method and the Time Difference Method. We checked the fact that the selected design factor affected starting characteristic of the Line-Start Permanent Magnet Synchronous Motor. Depend on this result we found the optimized design point by using the response optimization.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.8
• /
• pp.995-999
• /
• 2014

In this paper, a new size-reduction approach for branch-line coupler is introduced which uses parallel end-shorted coupled lines with lumped capacitors. The characteristic of the new design was analyzed using even-odd mode method, and simulated on HFSS before fabricated on the FR4 epoxy glass cloth copper-clad plat (CCL) PCB substrate at center frequency of 1 GHz. The electrical length of transmission line was reduced to 15 degrees, therefore the size of branch-line coupler was largely reduced approximately maintaining the same characteristic around the stable center frequency. The insertion loss of the branch-line coupler filter was -4.39 dB. The size of the overall hybrid is $20mm{\times}20mm$. Measurements results were well agreed with the simulated ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.4
• /
• pp.649-656
• /
• 2000

In this paper, a closed exact from and its approximation of the characteristic impedance of a lossy coaxial line with a thick outer conductor are proposed. It is also shown for 3.5mm reference air line that the proposed approximation is accurate over the entire operating frequency range of the line.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.12-14
• /
• 2005

This study investigates the characteristic analysis of Line-start Permanent Magnet Synchronous Motor considering skew effect. The effects of the skew on machine characteristic are analyzed by using direct co-simulation of Matlab Simulink and Flux2D. Validity of analysis method is confirmed by the analysis result of Non-skew Model.