• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.847-854
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• 1999

In this paper, we have analysed frequency-dispersion characteristics of higher-order modes for uniform planar transmission lines, using the 2-dimensional finite-difference time-domain method. The method presented in this paper uses both informations of amplitude and phase of the electromagnetic spectrum to determine resonant frequencies, while methods previously reported use the magnitude only. This algorithm is very useful when a resonant mode has a relatively small magnitude, where the identification of the resonant mode is quite difficult. Numerical results show that a strip line supports few higher-order modes within the frequency range of 20 GHz, but there occur many higher-order modes in the structure of grounded coplanar waveguide, where resonant frequencies of the first higher-order mode is very close to those of the fundamental mode and there occur lots of very adjacent higher-order modes. As in this example, for the analysis of planar transmission lines which support many resonant modes very close each other, the method presented in this paper can be applied very efficiently.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.451-462
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• 2024

In order to optimize the operational safety and reliability of the upper launcher for the CFETR ECRH system, a design of the launcher based on the remote steering concept is currently being carried out for comparison with the front steering equivalent. This paper presents the remote steering system's conceptual design and simulation analysis. A Square Corrugated Waveguide (SCW) of 65 × 65 mm has been designed with an optimized length of 9.35 m. By changing the relative length of the waveguide, the transmission efficiency of the SCW is optimized within the range of steering angles ±12°. Different error factors are investigated in detail, and corresponding acceptable error ranges are provided. Considering these error factors and ignoring ohmic losses and thermal effects, the relative transmission efficiency of the SCW is estimated to be >98 % within the steering angle range. A matching steering unit for the SCW is designed, which consists of an ellipsoidal focusing mirror and a steerable flat mirror. The detailed design of the steerable mirror motion trajectory is presented. Also, the influence of the possible beam incident errors caused by the steering unit on the transmission efficiency is analyzed in detail.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.237-243
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• 2017

This paper presents an analysis of the electromagnetic interference of a heterogeneous power bus where electromagnetic bandgap (EBG) cells are irregularly arranged. To mitigate electrical-noise coupling between high-speed circuits, the EBG structure is placed between parallel plate waveguide (PPW)-based power buses on which the noise source and victim circuits are mounted. We examine a noise suppression characteristic of the heterogeneous power bus in terms of scattering parameters. The characteristics of the dispersion and scattering parameters are compared in the sensitivity analysis of the EBG structure. Electric field distributions at significant frequencies are thoroughly examined using electromagnetic simulation based on a finite element method (FEM). The noise suppression characteristics of the heterogeneous power bus are demonstrated experimentally. The heterogeneous power bus achieves significant reduction of electrical-noise coupling compared to the homogeneous power buses that are adopted in conventional high-speed circuit design. In addition, the measurements show good agreement with the FEM simulation results.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.188-198
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• 2015

The validity of applying the Modified Airy Function (MAF) method to the problems of graded-index optical waveguides and graded potential barrier analysis was critically examined. In the former case, the method yielded very accurate results from the derived eigenvalue equations. In the latter case, however, the same method produced results that deviated significantly from exact numerical results for barriers with a smooth peak. The causes of the discrepancies were investigated in detail.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.366-370
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• 2003

This paper introduces a new design and fabrication technology of 28 GHz low-cost up and down converter modules for digital microwave radios, The design of the converter module is based on unit circuit blocks, which are to be characterized using a special test fixture. Based on the cascade analysis of the module the 28 GHz up and down converter modules have been designed and implemented. The measured module performance agrees with the cascade analysis. New components such as a tapped edge-coupled filter and a new Ka-band waveguide-to-microstrip transition, which are less sensitive to fabrication tolerances, have been used in the module implementation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.957-959
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• 2014

The wave analysis of cylinders combined rigidly with a finite plate to identify the effect of the plate on the wave propagation. This paper uses the mobility and impedance coupling method to combine a infinite-length cylinder with the plate, and obtains the coupling forces induced by the vibration of the structure. The waveguide finite element method is used to calculate the wave characteristics of the cylinder excited by the forces. From the results, the dispersion diagram can be obtained. It contains the characteristics induced by the vibration and length of the internal plate. It also shows the wave propagation of elastic waves sustained in the cylinder.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1893-1895
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• 1997

This paper presents an analysis of the electromagnetic field in the 3D microwave oven using computational method. The model is accounted the real shape, including the formings, input waveguide with the magnetron, tray, and so on. For quantisation of this problem, Galerkin method with the Nedelec's edge basic functions is used. The system of linear algebraic equations is solved by the iteration method. The simulation results were compared with the experimental results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.11
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• pp.80-87
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• 1993

In this paper, the fields of double-plane steps in rectangular waveduides are analyzed using the modified TE$_{mn}$$^{x}$ mode-matching method. The characteristics of rectangular waveguide having double-plane steps are investigated with accomdating the effects of higher-order modes generated by discontinuities. In comparison with the generalized TE$_{mn}$-TM$_{mn}$ mode analysis, the modified TE$_{mn}$$^{x}$ mode-matching method consumes less memory and CPU time and provides improved convergence behavior. The results obtained in this manner coinside with that of the TE$_{mn}$-TM$_{mn}$ mode-matching method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.103-105
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• 2003

The principle of the ultra-high frequency (UHF) method to detect partial discharge(PD) in GIS is to measure the UHF electromagnetic waves excited by PD pulses. Such electromagnetic waves propagate along the GIS busbar in the TEM-mode, TE-mode, TM-mode. And the coaxial busbar of the GIS acts as a waveguide in which the UHF electromagnetic waves travel. This paper was studied the analysis on damping characteristic of electromagnetic waves excited by PD in GIS and presented the method to yield the cutoff frequency for determine the minimum band of sensor that detect the PD pulse.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.4
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• pp.522-528
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• 1986

Based on the modified effective index method, analysis of dielectric rectangular waveguides and directional couplers are presented. Aside from the effective index concept of channel region, the equivalent index concept of cladding region is proposed. The error problem of eigenvalues, which has been experienced when the effective index method is used, is improved. Our approxiamtions give similar accuracy when compared with the results of other regorous approxiamtion techiniques. The advantage of the modified effective index methods is utilized by replacing the directional coupler with the equivalent slab guides, and the coupling constant is calculated by the coupled mode theory. The effectiveness of the equivalent index concept is positively confirmed.