• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1141-1146
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• 2004

The antenna array for receiving satellite broadcasting of Koreasat III is proposed. A cavity-backed slot antenna array is proposed to reduce feed line loss, increase the radiation efficiency, and make the feed network simple. A sub-array consists of $2{\times}4$ slot elements backed by a single cavity. By proper choice of dimensions it is shown that the proposed antenna has characteristics of the high radiation efficiency and the broad frequency bandwidth. Antenna characteristics for the array antenna with 256 elements are measured in Ku-band. A single cavity backed-sub-array has the gain of 18 dEi. The gam of the total antenna array(256 elements) is Over 33 dEi.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.48-52
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• 1995

Chipping is an unavidable phenomean in the slot grinding process of hard and brittle materials. However,it should be reduced for the improvement of surface integrity in the manufacture of optical and semiconductor components. Electrolytic In-process Dressing (ELID) technique for metal bonded superabrasive grinding wheel has been developed for mirror surface grinding of hard and brittle materials. Electrically dressed wheel surface has sharply exposed abrasives and results in lower grinding force, higher grinding efficiency in grinding. The paper deals with a newly developed method for slot grinding using ELID and was implemented to improve grooved surface quality and decreases chipping size on the edge of the groove. As a result, we accomplished shipping-free grooves and obtained the clear ground sufaces on glass and tungsten carbide.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.44-46
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• 2008

This paper presented the notch effect of interior permanent magnet motor(IPM) with compound variable number of pole and slot. The selection of proper pole and slot which makes characteristic and efficiency of motor is very important on motor design. The motor which has 6pole and 9slot is at base. This paper is choose the 4pole 6slot motor which has 2:3 ratio then analyzed the characteristic.

• Proceedings of the KIEE Conference
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• summer
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• pp.917-919
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• 2004

This paper deals with the stator design solution of a synchronous reluctance motor (SynRM) with various slot number by loss & torque evaluations related to the slot open, teeth width using coupled Preisach modeling & FEM. The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate the nonlinear solution. Comparisons are given with characteristics of a SynRM according to the stator winding, slot number, slot open, teeth width variation, respectively

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.41-49
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• 2015

In this paper, we studied an optimal design and efficiency improvement of the BLCD motor used in home electronic appliance. The number of stator slots is chosen depending on the rotor poles, phase number, and the winding configuration. In general, a fractional slots/pole design is preferred to minimize cogging torque. To reduce the winding resistance, we reduced the coil length and we improved the coil space factor. We proposed three types of stator slot shape design for the optimal BLDC motor design. One of them, U-type slot shape is a best optimal design, it proved by the simulated and tested. Optimal design of essential parameters aiming at high winding factor are presented to create for a high-quality system implementation. Design analysis is verified by testing and building a prototype motor.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1017-1018
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• 2007

Interior permanent magnet synchronous motor (IPMSM) for traction motor in the hybrid electric vehicle (HEV) has different parameters and characteristics according to pole and slot combinations. The fitting combination of pole and slot in the IPMSM improves characteristics of traction system ultimately. This paper deals with analyzing the characteristics of IPMSM for mild type HEV according to pole and slot combinations. Based on the result of characteristics, suitable pole and slot combination is presented to maximize efficiency of traction motor in the HEV system.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.9-12
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• 2003

Brushless do motors have been replacing brush type motors in machine tool and robotics applications over the last number of years This Paper deals with the design and application of the slot-less permanent magnet synchronous motor (PMSM). The slot-less PMSM eliminates rotational cogging torque due to permanent magnet preferred positions decreases core loss and thus increases efficiency, provides excellent torque-to-volume and power-to-volume ratios, and has a linear current versus torque relation. The PMSM with slot-less stator is designed and manufactured, which will be used for high speed and high efficiency application such a medical instruments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.381-386
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• 2014

In this paper, the effect of slot antenna's location in the radiation performance and impedance bandwidth was analyzed. The proposed antenna was designed to operate at Wi-Fi band(2.4~2.5 GHz) when the slot antenna is located at the center of the ground plane, the proposed antenna has a bandwidth of 340 MHz(2.24~2.58 GHz) under voltage standing wave ratio of = 2 and achieves average realized efficiency of 69 % over Wi-Fi bands.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.25-33
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• 2017

In this study, combustion tests were performed to investigate combustion performance of a pintle injector engine with double row rectangular slot which uses kerosene and liquid oxygens as propellants. The double row rectangular slot was designed to improve the combustion performance of a pintle engine with a single row and the blockage factor was changed from 0.7 to 1.0. The main design parameters of the double row were distance between rows, area ratio and aspect ratio. The characteristic velocity efficiency was measured from 92.4 to 96.9 percentage for double row but 86.8 percentage for single row. It showed the highest combustion performance at the BF 0.85.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3623-3627
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• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.