• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.156.2-156.2
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• 2015

반도체 소자의 크기가 나노사이즈로 줄어들기 때문에, 건식식각의 중요성이 강조되고 있다. dual plasma source를 사용함으로써 plasma 밀도, 이온충돌에너지, 이온플럭스를 조절 가능하다. Low frequency로 이온에너지를 조절하고, high frequency로 이온플럭스를 일반적으로 조절한다. 본 연구는 inductively coupled plasma (ICP)와 capacitively coupled plasma (CCP)를 사용하는 dual plasma source이다. ICP는 AE RPS로 2.4 MHz를 사용하고, CCP는 AE RFX-600으로 13.56 MHz이다. single L-probe는 Hiden ESPion이고, quadrupole mass spectrometer (QMS)는 INFICON CPM-300이다. chuck에 CCP가 인가되고, ICP는 SUS mesh를 거쳐서 영향을 미친다. Gas는 Ar, Ar+CF4 두 조건에서 비료를 하였다. Single L-probe를 이용하여 플라즈마를 측정한 결과 CCP만 인가하였을 때, Te 2.05 eV, Ne 4.07E+10 #/cm3, Ni 5.82E+10 #/cm3의 결과를 얻을 수 있었다. ICP를 방전하고 mesh를 통해서 chuck으로 입사하는 이온을 측정한 결과 mesh에 의해 이온이 중성화되어 거의 입사하지 않음을 확인할 수 있었다. 최종적으로 이온의 영향이 상쇄되고, 라디칼의 영향이 증가하여 높은 etch rate와 선택비를 가지며, 등방성 식각의 영향이 커질 것으로 사료된다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.47-53
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• 2003

In this paper we proposed a novel dual-band compact folded patch antenna with the same linear polarizations and high isolation characteristic between the two frequency range. The antenna is loaded with a high permittivity dielectric material in order to reduce the antenna size and open circuit stubs are used in order to broaden the bandwidth. The fractional bandwidths of the optimized antenna with demensions 4 mm${\times}$3 mm${\times}$5 mm are 3.0 % at 5.6 GHz band and 2.8 % at 5.8 GHz band, respectively. The isolation characteristic between the two ports is less than -26 dB within the operating frequency range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.379-387
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• 2000

In this paper, to transmit and receive the differently polarized wideband signals simultaneously with a single antenna system, the wideband, dual-frequency and dual-polarized(WDFDP) microstrip array antenna is proposed and designed. This antenna operates simultaneously at 14.25 GHz and 12.50 GHz. To extend to two dimensional array, microstrip feed line and coaxial probe through via-hole are used. The experimental results show that the proposed WDFDP microstrip antenna can be used in the compact portable terminals with a single antenna system and the characteristic of the resonators in this antenna produces a greatly enhanced bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1206-1211
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• 2006

In this paper, a Balun-BPF with the balun and BPF characteristics is proposed by using dual-mode ring resonator of $1{\lambda}$. We obtained the property of balun with the phase imbalance by symmetrically placing each output of ring resonator. The dual mode has been made by impedance difference between input and output lines. The fabricated Balun-BPF shows bandwidth of 40 MHz and insertion loss of 2.4 dB at a center frequency of 2.45 GHz. It shows the phase imbalance of $180{\sim}184$ degree and the magnitude imbalance of within 1 dB. The measured frequency responses agree well with simulated ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.497-499
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• 2013

In this paper, electrical lengths and impedances of a dual-mode resonator are calculated by using the transfer function of a dual-mode resonator by realizing the short-stub. The electrical length of transmission-line for a resonator is function of the frequency and the electrical length of stub is defined by the frequency and impedances of line and stub. Also, the inverter value of a bandpass filter using the dual-mode resonator is calculated. The effect of stub's impedance for inverter is very small. And, as the impedance of line is decreasing, the inverter value is increasing and as the bandwidth is increasing, the inverter value is increasing.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.635-644
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• 2002

Many generating units can be in parallel connection to one battery and inverter. However, one of the biggest problems we encountered is that wind speed is fluctuated sharply in accordance with the unstable weather conditions. To solve this problem, we need energy storage equipment such as storage lead-acid battery. We design a system and analyze its modeling so that it supplies a stable power to the load through DC-AC inverter part. In this paper, we applied dual step-up/down buck-boost converter and dual high-frequency half-bridge converter to the proposed system. These converters are used to store energy in the battery regardless of the change of the wind speed. The operation process of two proposed types of converters for high-power battery charging is discussed along with simulation and experimental result. We design a charging circuit which is applicable in the actual wind power generation system for 30kw and confirm the circuit's validity.

• Proceedings of the IEEK Conference
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• summer
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• pp.181-184
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• 2004

In this paper, we propose the dual band(2.4GHz and 5GHz) antenna for access point of WLAN(Wireless Local Area Network) which has similar radiation patterns for each band. Simulation results by using HFSS(High Frequency Structure Simulator) for the proposed antenna are presented. The electrical characteristics of the proposed antenna are measured with HP 8510C network analyzer and included. And radiation patterns are measured with rectangular anechoic far field antenna chamber. Measured results show that $S_{11}$ is less than - 14dB and VSWR(Voltage Standing Wave Ratio) is less than 1.5 for all frequency bands of interest. The measured maximum gain for elevation pattern at 2.40GHz is about 2.46dBi at $theta=-78^{\circ}$ and maximum gain for 5.825GHz is about 2.70dBi at $theta=-80^{\circ}.$ And the implemented antenna has good radiation pattern characteristic, therefore, we expect that the implemented dual band antenna is applicable for access point of WLAN.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.11
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• pp.1633-1640
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• 2013

In this paper, noise parameters for high frequency modeling of dual-gate FET are extracted and analyzed. To extract thermal noise parameter of dual gate, noise characteristics are measured by changing input impedance of noise source using Tuner, and the influence of pad parasitic elements are subtracted using open and short dummy structure. Measured results indicated that the dual-gate FET is improved the noise figure by 0.2dB compared with conventional cascode structure FET at 5GHz, and it confirmed that the noise figure has dropped due to reduction of capacitances between the drain and source, gate and drain by simulation and analysis of small-signal parameters.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1500-1511
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• 2017

The purpose of this paper is to study a high-performance control scheme for neutral-point-clamping three-level (NPC-3L) inverter fed dual three-phase permanent magnet synchronous motor (PMSM) drives by considering some asymmetric factors such as the non-identical parameters in phase windings. To implement this, the system model is analyzed for dual three-phase PMSM drives with asymmetric factors based on the vector space decomposition (VSD) principle. Based on the equivalent circuits, PI controllers with feedforward compensation are used in the d-q subspace for regulating torque, where the cut-off frequency of the PI controllers are set at the twice the fundamental frequency for compensating both the additional DC component and the second order component caused by asymmetry. Meanwhile, proportional resonant (PR) controllers are proposed in the x-y subspace for suppressing the possible unbalanced currents in the phase windings. A dual three-phase space vector modulation (DT-SVM) is designed for the drive, and the balancing factor is designed based on the numerical fitting surface for balancing the DC link capacitor voltages. Experimental results are given to demonstrate the validity of the theoretical analysis and the proposed control scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.47-54
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• 2005

The design method for a dual frequency antenna using CPW feed lines is presented. The antenna structures can be simplified by CPW feed lines and easily designed on integrated circuits. The presented antenna has two resonant frequency ranges and each respective resonant frequency is determined by its own length of monopole antenna. We used an impedance matching method by using a monopole coupling related to the ground of CPW feed lines As a result, the resonant frequencies were 5.25[GHz] and 23.5[GHz] and their bandwidths $35.2\%,\;and\;41.3\%$, respectively, and also, the separation of the two frequencies $370\;%$. We presented an analytical designing method to implement a dual frequency monopole antenna and showed simple antenna structures having two frequency ranges for RFIC Integrations.