• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.48-54
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• 1995

Dielectrically filled parallel-plate waveguide with finite number of periodic slots in its upper plate as a leaky wave antenna is analysed for E-polarization case. The integro-differential equation whose unknown is the slot equivalent magnetic current over the slot is formulated and solved by use of Galerkin's method. From knowledge of the equivalent magnetic current, the propagation constant and radiation pattern for the finite periodic structure are determined and compared with the results of the infinite case. Good correspondence between them is observed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.25-35
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• 1995

An analysis method of electromagnetic coupling through an arbitrarily shaped aperture on the upper wall of parallel-plate waveguide, when excited by an electromagnetic plane wave from outside, is considered. The mixed-potential integral equation, in which Green's functions are expressed in a computationally efficient closed form by using the Prony's method and the Sommerfeld identity, is formulated. Expanding the unknown equivalent magnetic surface current in terms of two-dimensional rooftop-type basis functions and choosing razor testing, the integral equation is reduced to a linear algebraic equation, which is solved. The results are compared with the previous results. Fairly good agreements between them are observed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.985-988
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• 2017

Magnetic induction (MI) based communication is one of the near-field communication techniques, which makes use of induced magnetic fields. In order to develop the MI based underwater communication networks, we evaluate and compare the loss performance between direct-MI and MI-waveguide in underwater environment.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.6
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• pp.263-267
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• 2004

A new type of interaction circuitry for a broadband gyro-TWT is presented in this paper. A method for the analysis of dispersion characteristics of a periodic structure, which is composed of conducting posts in a rectangular waveguide, is presented. This method utilizes a mode matching technique and equivalent circuit model. The calculated and measured results demonstrate that this periodic structure could be utilized for the interaction circuit of a wide band Gyro-TWT.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.422-425
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• 1988

The structure consisting of an E-plane dielectric slab partially filling a rectangular waveguide is examined with attention on those higher order mode propagation characteristics that are relevant to the design of nonreciprocal remanence ferrite phase shifters. The mechanisms for the elimination of $LSE_{11}$, $LSM_{11}$, $LSE_{12}$ modes are introduced. Experimental verification of elimination of higher order mode is shown in the form of insertion loss measurements.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2431-2433
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• 1999

Phase errors of arrayed waveguide degrade the performance of AWG router, especially for dense WDM system. So it is necessary to measure the phase error and to compensate. The analysis method of the interference signal from the low coherence interferometer to measure the path length difference phase error is studied. The interference signal generated assuming the intentional path length difference errors of 0.1$\sim$0.4${\mu}m$ are analyzed and the results show that the path length difference phase error of ${\Delta}L$ within ${\pm}14^{\circ}$ of sampling phase error can be accurately measured.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.118-123
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• 2011

A novel triangular-shaped plasmonic metal-insulator-metal (MIM) Bragg grating waveguide is introduced, whose band-gap is narrower than that of the conventional step type and wider than that of the sawtoothshaped one. Moreover apodized triangular-shaped MIM Bragg grating structures are proposed in order to reduce the side lobes of the transmission spectrum, because the Bragg reflector with a sawtooth profile has a smoother transmission spectrum than that of a triangular-shaped one. The performance of the proposed structures is simulated by using the finite difference time domain method.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.91-94
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• 2012

Arrayed waveguide grating (AWG) phase errors are normally assessed from the Fourier transform of the interference intensity data in the frequency domain method. However it is possible to identify the phases directly from the intensity data if one adopts a trial-and-error method. Since the functional form of the intensity profile is known, the intensities can be calculated theoretically by assuming arbitrary phase errors. Then we decide the phases that give the best fit to the experimental data. We verified this method by a simulation. We calculated the intensities for an artificial AWG which is given arbitrary phases and amplitudes. Then we extracted the phases and amplitudes from the intensity data by using our trial-and-error method. The extracted values are in good agreement with the originally given values. This approach yields better results than the analysis using Fourier transforms.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1213-1215
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• 1994

The shape of lossy material inside a waveguide matched load is optimally designed to give low reflection over a given frequency range. The 3 dimensional vector finite element mettled is used as an analysis tool which does not generate spurious mode. The optimizing process used in this parer is the Powell technique. The designed load gives the low reflection about -30 dB around 10GHz with 1.5 wavelength of the load length.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.43-50
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• 1995

In this paper, the variational method are used for the filter analysis methods and a CAD program for the design of the waveguide low-loss bandpass filters using inductive window structures for the VSAT(Very Small Aperture Terminal) system has been developed based on the passband correction method combined with fiter synthesis procedures. Using the developed CAD program, 0.01dB equi-ripple chebyshev type 6-section bandpass filters which are sued in the VSAT system operating nationally are designed for the purpose of the Down-link of 12.75~13.25GHz and the Up-link of 14.0~14.5GHz, fabricated and mesured. The measured results are good agreement woth the theoretical resuls.