• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.982-988
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• 2005

An analytic solution of circular aperture antenna with a feed transition is presented using a hybrid method of generalized scattering matrices and integral transform. The method can give an analytic solution to antennas with integrated filters or mode converters, etc. Scattering matrices and integral transform techniques are combined to accommodate discontinuities connected between an aperture and a feed waveguide, and radiated field from the aperture. The method gives radiation fields as well as return losses of the antenna.

• Journal of Power Electronics
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• v.11 no.1
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• pp.37-44
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• 2011

In this paper, a four-phase 8/6-pole 4-kW SR motor drive model is presented. Based on experimental data, the model allows an accurate simulation of a drive in dynamic operation. Simulations are performed and a laboratory type set-up is built based on a TI TMS320F2812 platform to experimentally verify the theoretical results obtained for a SR motor. To reduce acoustic noise and to correct the power factor of this drive, a two-stage power converter is proposed that uses a current source rectifier (CSR) as the input stage for the asymmetrical converter of the studied SRM. Employing the space-vector modulation (SVM) method in matrix converters, the CSR switching allows the dc link's capacitors to be eliminated and the power factor of the SRM drive to be improved. As the electrical motive force (emf) is directly proportional to the rotor speed, the input voltage to the machine can be programmed to be a function of the speed with the modulation index of the CSR, leading to a reduction in the acoustic noise of the SRM drive. Simulation of the whole SRM drive system is performed using MATLAB-Simulink. The results fully comply with the required conditions such as power factor correction with an improvement in the THD.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2427-2429
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• 2005

OLED in the spotlight of display market has advantages of low power driving, self-emission and fast response. But it has disadvantages of inefficient luminescence and high power consumption. Most of PM(passive Matrix) DC-DC converters in common use is using voltage divider. This voltage divider type has some difficulties of suitable electric device selection for voltage division and of the stabilized output due to feedback current trimming. Therefore, noise analysis and power solution in OLED are important technologies having an effect on electric characteristics. In this dissertation, we have obtained the stable output by using digital signals in multi-channel DC-DC converter, the profit of power consumption reduction of driving source and economical efficiency in the PCB board size.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.376-383
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• 2005

We designed and fabricated integrated-optic tunable polarization controllers based on $LiNbO_3$ with the Ti-indiffused waveguide along the y-axis utilizing the electro-optic effect. The device consists of $TE↔TM$ mode converters and TE/TM phase shifters. We analyzed the operation principles of each device utilizing transfer matrices based on a Jones matrix and simulated shifting of the center wavelength by inducing voltage. We confirmed experimentally that the fabricated devices control the tunability of the center wavelength and the input SOP.