• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.375-381
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• 2002

A rigorous analysis of a broad wall slot array is presented. The slot is longitudinal and offset from the center line in the rectangular waveguide. Pertinent integral equations are developed, taking into account finite wall thickness. The mothed of moment with entire basis function is used to solve a pair of coupled-integral equations, derived from the electromagnetic boundary conditions using modified Green's function, to find the tangential electric field on the upper and lower surfaces of the slot. Numerical results for resonant length and scattering parameters of the slots are Presented over a range of offset. Computed results are compared with experimental result.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.589-595
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• 2008

Detent force of a permanent magnet linear motor(PMLSM) consist of cogging and drag forces, and should be minimized for high precision control purpose applications. This paper shows that the cogging force can be reduced effectively by employing 9 pole 10 slot structure. The drag force is minimized by optimizing the total length and shape of the exterior teeth of armature core simultaneously by using($1+{\lambda}$) evolution strategy coupled with response surface method. After optimization, the optimized PMLSM is proven to reduce 95% and 92.6% of the cogging and total detent forces, respectively, and give 12% and 6.4% higher Back-emf and thrust force, respectively, compared with a conventional 12 pole 9 slot structure under the same condition. Additionally, Simulation results by the proposed optimum design are verified by the experiment results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1363-1368
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• 2015

Aperture-coupled circular polarization microstrip array antenna is proposed in this paper. The proposed antenna is useful for 2.4GHz ISM band and its aperture shape is a modified H-slot. The optimal design parameters for the antenna structure is found by using electromagnetic analysis tool HFSS repeatedly. The HFSS simulation results, such as return loss, axial ratio, radiation pattern and gain of the proposed array antenna are compared with results of the single antenna. It is able to verify that the proposed array antenna is valuable enough to be used in various applications as well as 2.4GHz ISM band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.75-80
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• 2003

This paper presents novel compact circularly polarized(CP) operation of a annular ring slot antenna with a 45$^{\circ}$truncated in the patch and a cross-slot of unequal slot lengths. A simple configuration based on a cross-slot of unequal slot lengths on the annular ring patch is adopted to realize a small-size element antenna and used a proximity coupled feed method. Experimental results show that much wider impedance bandwidth of 7.74 % and axial ratio bandwidth of 1.9 % in GPS band(1.5 GHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.636-644
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• 1999

Experimental and simulation results are presented on the Aperture-Coupled microstrip patch antennal with U-shaped slot. Experiment and simulation results include impedance bandwidth, copolar and crosspolar-pattern characteristics and gain measurements. Simulation results show the advantages of U-slotted patch antenna comparing with the normal patch antenna. More than 35% impedance bandwidth is obtained with reasonably restricted cross-polar radiation pattern. The U-slotted radiation element fed by aperture-coupling method can be more easily extended to array structure, compared with that fed by coaxial cable.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.5
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• pp.36-44
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• 1993

In this paper, a simple design method is represented for a contiguous-band waveguide manifold diplexer which employs a half-wavelength line at the input port of the singly terminated bandpass filterand has resonant-slot coupled E-plane T-junctions. This design method is based on the fact that the input impedance characteristics of the singly terminated bandpass filter are approximately unchanged when a resonant slot and a half-wavelength line at the input port of the filter are employed. This design method is also applicable to the design of the multiplexer. A contiguous-band waveguide manifold diplexer using the post coupled cavity filters is designed, constructed, and tested. The computed and experimental results show the validity of the theory.

• Journal of IKEEE
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• v.22 no.3
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• pp.793-799
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• 2018

An improved design of Ultra Wide Band(UWB) Bow-Tie antenna, which can control an enhanced wide stop-band, is presented. The mutually coupled slot-pair improves and controls the rejection band. The UWB antenna is composed of an electromagnetically coupled Bow-Tie patch and a parasitic ground patch, whose working frequency is extended to full UWB range in this work. By adding slot-pairs on the main patch and optimizing, they can give any requested wide rejection bands and sharp skirt characteristics, as is often required for UWB antennas and multi-band antennas. All the parameters are precisely calculated by an adequate optimization method. The Particle Swarm Optimization(PSO) technique is appropriately adopted. The proposed design and method is proved to give and control the sharp-skirt wide stop-band to UWB Bow-Tie antennas.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.6
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• pp.1-5
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• 1983

A new equation, which enables us to calculate the characteristics of coupled slot-lines on a dielectric substrate, is derived. Their calculations are based on the single slot-line analysis of S.B. Cohn, but each equation of total admittance in the even mode and the odd mode is derived by a different approach. The results agree with Knorr and Kuchler's data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.39-51
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• 2014

This paper deals with design of a direct-coupled, small-scaled permanent magnet generator (PMG) for wind power application. First, this paper determines rated power and speed of the PMG from measured characteristics of wind turbines. Second, we derive analytical solutions for the open-circuit field in order to determine optimum magnet thickness and pole pitch/arc ratio. Third, on the basis of open circuit field solutions, stator magnetic circuit including slot opening, teeth width and yoke thickness is designed. And then, a diameter of stator coil which agree with a required current density is calculated, and its turns are determined from the area of slot considering winding packing factor. Finally, finite element (FE) method is employed in analyzing the details of the designed PMG and, test results such as back-emf measurements are given to confirm the design.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.465-470
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• 2007

This paper is designed and producted the microstrip patch antenna which used aperture coupled feed structure, and had a comparatively hish gain and headband characteristic with a PCS substitution repeater antenna. The proposed antenna transformed a coupled slot into a H-type in order to improve a characteristic of a general aperture coupled feed antenna. It is this H-type form slot reduces back lobe from the antenna backside at the same time that a coupling between a power feed and patches is iccreased, and to have maximized a gain of an antenna. As a result of having measured the antenna which the VSWR was 1.5 or below and tied up the gain than 7.5dBi in the $1750{\sim}1870$[MHz] that was a PCS substitution, and a beamwidth became in $80^{\circ}$ and radio waves shadow was local, but accomplishment did PCS mobile communication service in building me smoothly, but confirmed what practical use can become.