• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.137-150
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• 1997

The problem of electromagnetic coupling into a thin conducting wire through a slot in an infinite conducting is analyzed by use of MPIE(mixed potential integral equation) and two- dimensional moment method using subsectional(rooftop) basis functions. The equivalent circuit is derived using a center-repesentation method which is valid in a narrow slot case. The equi- valent magnetic currents on the slot and the induced currents on the wire are caculated respec- tively, for the TM wave is incident upon the slot with arbitrary angle of incidence. The theoretical transmission coefficients of transmission line which is composed of thin-wire and infinite conducting plate with a narrow slot are compared and found to be in good agreement with experimental results.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.37-44
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• 2020

In this paper, we proposed a compact printed monopole antenna with an inverted L-shaped slot for dual-band operations. Two operating frequency bands are achieved with the use of an inverted L-shaped slot etched on the radiating strip for bandwidth enhancement and a defected ground structure for return loss improvement in the higher frequency band. The measured results showthat the proposed antenna has impedance bandwidths (S₁₁< -10 dB) of 270 MHz (1.81-2.08 GHz) and 340 MHz (2.36-2.70 GHz), covering the required bandwidths for PCS (1850.5-1989.5 MHz), CDMA 2000 (1850-1990 MHz), TD-SCDMA (1880-2025 MHz) and 2.4 GHz WLAN (2400-2484 MHz). The measured return loss of the proposed antenna has a good value of approximately 27.2 dB at 2.4 GHz WLAN. The antenna's peak gains also have a high value of 1.92 dBi at 2 GHz and 2.12 dBi at 2.45 GHz. The proposed antenna shows omnidirectional radiation patterns over the entire frequency range of interest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.965-971
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• 2001

In this paper, the triangular u-slot patch antenna for the PCS & IMT-2000 dual band are studied. The frequency bandwidth of a triangular u-slot patch antenna can be increased by L-strip fed structure. The impedance bandwidth(VSWR$\leq$2) of the fabricated single element is 590 MHz(30.18 %). Using the frequency bandwidth of PCS & IMT-2000, we confirm VSWR below 1.65, which is a good characteristic. Thus the wideband characteristic of the L-strip fed structure is confirmed experimentally.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.837-839
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• 2000

Capacitor-run single induction motors have the unbalanced elliptic rotating magnetic field so that it is difficult to analyze the characteristic and calculate the accurate slot leakage reactance of the rotor with the closed slot by using the lumped parameter. In this paper, the characteristic is analyzed by the symmetrical coordinate method in terms of the lumped parameter coupled with the numerical analysis. The secondary parameters are calculated by the one slot pitch boundary condition applying to Finite Element Method (FEM). The analysis results are compared with experimental ones.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.829-835
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• 1990

We proposed a new radiating structure generating a circularly polarized wave. Futhermore, we show that it is possible to generate all kind of polarizations by simple variations of some schematic factors. Basically, the structure composed of a slot and a strip. The length of slot and strip, the slot-strip distance and the strip inclination are the crucial factors to determine the polarization form. In this paper, we investigated the effects on polarization and other radiation characteristics by varying the factors.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.41-43
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• 1993

This paper is proposed a method that optimizes teeth shape of Linear induction motor for high efficiency and slot shape for static end effect minimization in linear induction motor. As a result, unbalance current of each phase in minimized.

• Current Optics and Photonics
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• v.6 no.3
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• pp.323-331
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• 2022

Electro-optic modulator (EOM) takes a vital role in connecting the electric and optical fields. Here, we present a heterogeneously integrated EOM based on the lithium niobate-on-insulator (LNOI) platform. The key modulation waveguide structure is a field-enhanced slot waveguide formed by embedding silicon nanowires in a thin-film lithium niobate (LN), which is different from the previously reported LN ridge or etchless LN waveguides. Based on such slot structure, optical mode field area is reduced and enhanced electric field in the slot region can interact well with LN material with high Electro-optic (EO) coefficient. Therefore, the improvements in both aspects have positive effects on enhancing the modulation performance. From results, the corresponding EOM by adding such modulation waveguide structure achieves better performance, where the key half-wave-voltage-length product (V_𝜋L) and 3 dB EO bandwidth are 1.78 V·cm and 40 GHz under the electrode gap width of only 6 ㎛, respectively. Moreover, Lower V_𝜋L can also be achieved. With these characteristics, such field-enhanced waveguide structure could further promote the development of LNOI-based EOM.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.1-8
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• 2001

This study deals with the experimental and numerical investigations to design the high performance otter board. Experiment was carried out to determine the most effective slot size of single-slot cambered otter board in the circulation water channel of BAEK KYUNG IND. Co. LTD. Numerical analysis was done by the commercial CFD code, FLUENT, to provide some valuable physical interpretations and finally to design the otter board section by numerical method. The major results are as follows ; 1. In experiment, the maximum lift and drag coefficients of simple cambered type otterboard were 1.41, 0.55, respectively, at the angle of attack $28^\circ$, while those of slot one with slot size 0.02C (C denotes the chord length) were 1.72, 0.42 at the angle of attack $24^\circ$. 2. The hydrodynamic characteristics depending upon slot size shows the greatest at 0.02C of the slot size. 3. Numerical results well visualized the streamlines, pressure fields, and speed vectors of a simple cambered and slot cambered otter board with slot size 0.02C. The slot cambered one with slot size 0.02C was shown that pressure field was distributed moderately on front and back side of otter board. And, the delay and decrease of separation were favorably achieved by flow through slot. 4. Computed result on the pattern of hydrodynamic field and the values of $C_L$ and $C_D$ by the commercial CFD code, FLUENT, show almost the same as those of the experimental result.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.33-39
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• 2021

In this study, we tried to find the correlation of the parameters and dual resonance of U-slot microstrip patch antenna with L-shaped Inset-feed structure and design broadband antenna using them. In the first step, we classified cases where dual resonance occurs through changes in antenna parameters that affect antenna performance. In the second step, we correlated each antenna parameter to the location and intensity of the resonance point, and 3 dB bandwidth. Next, antenna simulation confirmed the process of designing to have wide bandwidth using the correlation in the second step previously presented in the U-slot antenna case with narrow bandwidth. Finally, we fabricated a designed antenna and demonstrated the validity of antenna bandwidth broadening through the correlation analysis.

• Tribology and Lubricants
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• v.33 no.5
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• pp.187-201
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• 2017

This paper presents the impact of couple stress lubricant on performance of slot-entry hydrostatic/hybrid journal symmetric/asymmetric bearings. Reynolds Equation using Finite Element Technique has been solved for the flow of couple stress and Newtonian lubricants in bearings. The results have been computed for concentric design pressure ratio(${\beta}^{\ast}=0.5$), slot width ratio (SWR = 0.25) and chosen parameters of couple stress lubricant ${\bar{l}}=5$, 10, 15. It is observed that numerically simulated outcomes for slot-entry journal bearings, considering the influence of couple stress lubricant indicate a substantial improvement in the performance of the bearing.