• Electrical & Electronic Materials
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• v.8 no.2
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• pp.204-210
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• 1995

The characteristics of the internal circuits and the load capacitance should be included to optimize the size of BiCMOS buffer. In order to get the optimum size and delay time of the BiCMOS buffer, new size plane is suggested. By using the size plane, the optimum characteristics of CMOS buffer according to the number of stages can be obtained. From this method, delaytime, .tau.$_{D}$, is obtained 2.39 nsec with $V_{\var}$=5V, $C_{L}$=5pF, W=30.mu.m and $A_{e}$=135.mu. $m^{2}$.>..>...>.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.173-176
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• 2002

An efficient design method for E-plane waveguide bandpass filter has been developed. The analysis method for E-plane discontinuities with finite length is based on Generalized Scattering Matrix (GSM) method. Furthermore, the design portion is based on the filter synthesis method. Waveguide bandpass filters designed with this method have been fabricated and measured. Excellent agreements with design have been obtained

• Journal of Magnetics
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• v.16 no.2
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• pp.161-163
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• 2011

We report results of first principles calculations for effects of an external electric field (E-field) on the magnetocrystalline anisotropy (MCA) in transition-metal (Fe, Co, and Ni) monolayers and at metal-insulator (Fe/MgO) interfaces by means of full-potential linearized augmented plane wave method. For the monolayers, the MCA in the Fe monolayer (but not in the Co and Ni) is modified by the E-field, and a giant modification is achieved in the $Fe_{0.75}Co_{0.25}$. For the Fe/MgO interfaces, the ideal Fe/MgO interface gives rise to a large out-of plane MCA, and a MCA modification is induced when an E-field is introduced. However, the existence of an interfacial FeO layer between the Fe layer and the MgO substrate may play a key role in demonstrating an Efield-driven MCA switching, i.e., from out-of-plane MCA to in-plane MCA.

• Smart Structures and Systems
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• v.26 no.4
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• pp.435-449
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• 2020

To effectively extract the vast wind resource, offshore wind turbines are designed with large rotor and slender tower, which makes them vulnerable to external vibration sources such as wind and wave loads. Substantial research efforts have been devoted to mitigate the unwanted vibrations of offshore wind turbines to ensure their serviceability and safety in the normal working condition. However, most previous studies investigated the vibration control of wind turbines in one direction only, i.e., either the out-of-plane or in-plane direction. In reality, wind turbines inevitably vibrate in both directions when they are subjected to the external excitations. The studies on both the in-plane and out-of-plane vibration control of wind turbines are, however, scarce. In the present study, the NREL 5 MW wind turbine is taken as an example, a detailed three-dimensional (3D) Finite Element (FE) model of the wind turbine is developed in ABAQUS. To simultaneously control the in-plane and out-of-plane vibrations induced by the combined wind and wave loads, another carefully designed (i.e., tuned) spring and dashpot are added to the perpendicular direction of each Tuned Mass Damper (TMD) system that is used to control the vibrations of the tower and blades in one particular direction. With this simple modification, a bi-directional TMD system is formed and the vibrations in both the out-of-plane and in-plane directions are simultaneously suppressed. To examine the control effectiveness, the responses of the wind turbine without control, with separate TMD system and the proposed bi-directional TMD system are calculated and compared. Numerical results show that the bi-directional TMD system can simultaneously control the out-of-plane and in-plane vibrations of the wind turbine without changing too much of the conventional design of the control system. The bi-directional control system therefore could be a cost-effective solution to mitigate the bi-directional vibrations of offshore wind turbines.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.257-259
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• 1990

In the design of waveguide E-plane bandpass filter, it is very important to characterize the K-inverters. In the analytical method. losses arising from the metal and the dielectric are ignored for the simplicity of design process. In this paper, based on the new measurement method, characteristics of inverters are measured and compared with those calculated based on mode-matching analysis.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.59-67
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• 2013

The radiation characteristics of an E-plane linear array antenna composed of inductive loaded patch antennas (ILPAs) are investigated. The radiation characteristics of an ILP array antenna are significantly improved compared to those of a conventional array antenna because the mutual coupling of an ILP array antenna is very small. The patch length of a $5{\times}2$ ILPA for the enhancement of the radiation characteristics of a 5-element E-plane linear array antenna composed of ILPAs is presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.108-114
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• 1998

This paper presents the design and fabrication of waveguide E-plane metal insert bandpass filter for milli-meter waves which is analyzed transmission characteristics by calculating the generalized scattering matrix using mode-matching method. The bandpass filter was fabricated to verify the proposed method by the WR-34 rectangular waveguide to operate in 30.085 ~ 30.885 GHz. The fabricated waveguide E-plane metal insert band- pass filter was established the fact that it is so adaptive for milli-meter waves due to the measured data closely consistent with the results of analysis using mode-matching method, that is, the maximum value of insertion loss is 0.8 dB and the return loss is below -15 dB.

• Smart Media Journal
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• v.4 no.4
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• pp.64-69
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• 2015

In this paper, we have proposed a tapered slot antenna for UWB communication system. The tapered slot antenna has directional radiation and broad bandwidth. Proposed tapered slot antenna is designed using Ansys Inc. HFSS and its VSWR, return los, and radiation pattern is analyzed. Operating band of the antenna were satisfied -10 dB S11 and $VSWR{\leq}2$ in 2.7 ~ 4.8 GHz band. The radiation pattern of the antenna is showed in E-plane (YZ plane) and the H-plane (XZ plane) and the highest gain of 7.3 dBi is seen at 4.5 GHz. Therefore, proposed tapered slot antenna has wide bandwidth characteristic and directional for location awareness.

• Journal of the Korean Mathematical Society
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• v.44 no.6
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• pp.1313-1327
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• 2007

We review the algebraic structure of $\mathbb{H}{\sharp}$ and show that $\mathbb{H}{\sharp}$ has a scalar product that allows as to identify it with semi Euclidean ${\mathbb{E}}^4_2$. We show that a pair q and p of unit split quaternions in $\mathbb{H}{\sharp}$ determines a rotation $R_{qp}:\mathbb{H}{\sharp}{\rightarrow}\mathbb{H}{\sharp}$. Moreover, we prove that $R_{qp}$ is a product of rotations in a pair of orthogonal planes in ${\mathbb{E}}^4_2$. To do that we call upon one tool from the theory of second ordinary differential equations.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.347-348
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• 2008

We investigate the characteristics of a dipole antenna on an artificial magnetic conductor (AMC) constructed of a normal material and a ground plane. We studied how the antenna performance is affected by changes in the dipole length and the distance between the dipole and the ground plane. The relation between the reflection phase of the AMC and the input resistance of the dipole for input impedance matching is also verified.