• Journal of Advanced Navigation Technology
• /
• v.18 no.4
• /
• pp.371-375
• /
• 2014

In this paper, the solutions of TE(transverse electric) scattering problems by a resistive strip grating over a grounded dielectric layer are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients and the resistive boundary condition is used for the relationship between the tangential magnetic field and the induced surface current density on the resistive strip. The induced surface current density of resistive strip is obtained by difference of the up and down of the magnetic field in two boundary areas of the resistive strip. The numerical results for reflected power of zeroth order mode analyzed by according as the resistivity, the width and spacing of resistive strip, the relative permittivity and thickness of dielectric layer, and incident angles. The numerical results shown in good agreement compared to those of the existing papers using FGMM(fourier galerkin moment method).

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.4
• /
• pp.21-26
• /
• 2019

In this paper, TE(transverse electric) scattering problems by a resistive strip grating between a double dielectric layer are analyzed by using the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the resistive boundary condition is applied to analysis of the resistive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of resistive strip, the relative permittivity and thickness of the double dielectric layers, incident angles, and uniform resisitivity. Typically, the reflected power for the conductive strip increased as the value of the relative dielectric constant increased, the reflected power for the resistive strip with uniform resistivity decreased as the value of the resisvivity increased. The numerical results for the presented structure of this paper are shown in good agreement compared to those of the existing papers.

• Journal of the Korean Society of Safety
• /
• v.2 no.3
• /
• pp.21-27
• /
• 1987

The effect of plastic deformation in an interfacial crack is considered. Yield zones are assumed to have the form of a strip along the interface. The crack is subjected to mode III loads at infinity and lies along the interface of two semi-infinite planes with different material properties. The size of the yield zones, the relation between the size of the yield zone and CTOD are obtained in a closed form solution. The J integral also can be obtained in a closed form Solution.

• Korean Journal of Optics and Photonics
• /
• v.19 no.1
• /
• pp.73-79
• /
• 2008

We propose a novel metal-waveguide structure for sustaining long-range surface-plasmon-polaritons (LRSPP). The LRSPP waveguides are composed basically of two asymmetric metal layers: a very thin, finite-width metal strip on top of a metal slab with a dielectric gap in between them. Mode cut-off of LRSPPs excited on the double-metal waveguides is characterized by consistently investigating their dispersion relations and mode profiles. We also confirm experimentally the existence of low-loss, well-confined LRSPP modes by measuring far-field outputs emerging from an edge of the asymmetric double-metal waveguides. In the experiment, we have fabricated several types of SPP waveguide devices including straight lines, S-bend, and Y-branch consisting of gold strips (20 nm-thick, $5{\mu}m$-wide). Overall propagation loss of the proposed double-metal waveguides is quite comparable to that of single metal-strip waveguides, in addition the mode sizes can be tuned by increasing the core-insulator gap between the metal layers to get a higher coupling efficiency with a single-mode fiber in telecom wavelength. The proposed LRSPP waveguides may open up realization of SPP-waveguide sensors or nonlinear SPP-devices by replacing the core-insulator with a bio-fluid or a nonlinear medium.

• Journal of Mechanical Science and Technology
• /
• v.16 no.1
• /
• pp.39-45
• /
• 2002

Initiation and propagation of interfacial crack along bimaterial interface are considered in this study. A biaxial loading device for a single specimen is used for obtaining a wide range of mode-mixities. The specimen is an edge-cracked bimaterial strip of glass and epoxy; the biaxial loading device, being capable of controlling displacements in two perpendicular directions, is developed. A series of interfacial crack initiation and Propagation experiments are conducted using the biaxial loading device for various mixed modes. Normal crack opening displacement (NCOD) is measured near crack front by a crack opening interferometry and used for extracting fracture parameters. From mixed mode interfacial crack initiation experiments, large increase in toughness with shear components is observed. The behavior of interfacial crack propagation analyzed as a function of mode-mix shows that initial crack propagation is delayed with increase of mode-mixity, and its velocity is increased with positive mode-mixity but decreased with negative case. However, it is found that crack propagation is less accelerated with positive mode-mixity than the negative mode-mixity, which may be caused by contact and/or effects of friction between far field and near-tip Held along the interfacial crack.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.7
• /
• pp.109-116
• /
• 1998

In this work was produced and analyzed a z-cut Ti:LiNbO$_{3}$ optical waveguide which applies for various optical devices.A waveguide channel with a thickness 8 .mu.m and a length 66,000.mu.m and a mach-zehnder interferometer type waveguide were fabricated at a diffusion temperature 1050.deg. C for 6-8hours in a wet $O_{2}$ environment. The resulting Ti:LiNbO$_{3}$ optical waveguide was measured to have a Ti-strip thickness of 950.angs. and low loss. Surfaces and cross-sections of a fabricated waveguide were analysed. The mode pattern anaysis revealed that the waveguide showed a single mode at a 1550nm wavelength. The effective dimension of the waveguide was calculated by measuring a gaussian profile; Wx=10.95.mu. and Wy=9.14.mu.m. a propagation loss, of 0.50dB/cm for a TM mode and 0.45dB/cm for a TE mode, was low enough to be accepatable for optical devices.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.6
• /
• pp.46-52
• /
• 1985

A theoretical study of mutual coupling effects between two H-plane coupled microstrip patch antennas is presented. The radiation resistance and slot capacitance of a single micro-strip patch are calculated. To investigate the mutual coupling effects, the even and odd mode characteristic impedance and effective dielectric constants are obtained using the coupled microstrip line model. The S-parameter matrix elements 511,512 are used to study the mutual coupling e(facts in S-band frequency ranges for various patch spacings. Theoretical results and measurements are in good agreement.

• The Journal of Information Technology
• /
• v.4 no.3
• /
• pp.77-86
• /
• 2001

In this paper, Electromagnetic scattering problem by a resistive strip grating with 2 dielectric layers on a ground plane according as resistivity of resistive strip, relative permittivity and thickness of dielectric layers, and incident angles of a electric wave is analyzed by applying the PMM (Point Matching Method) known as a numerical procedure. The scattered electromagnetic fields are expanded in a series of floquet mode functions. The boundary conditions are applied to obtain the unknown field coefficients and the resistive boundary condition is used for the relationship between the tangential electric field and the electric current density on the strip. According as the relative permittivity and the thickness of layers are increased, the values of the geometrically normalized reflected power have a high value and the values of strip width are moved toward a high value going from left to right. When the resistivity of this paper has a value of zero, the numerical results of the geometrically normalized reflected power show in good agreement with those by the PMM of existing paper. Then, the most energys of the sharp variation point in minimum values of the geometrically normalized reflected power are scattered in direction of the other angles except incident angle.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.3 s.36
• /
• pp.407-421
• /
• 1998

The purpose of this paper is to provide and verify an analytical method, based on the spline finite strip method, which can be used to investigate the buckling mode and stress of thin-walled steel sections. Geometric imperfection and initial stress of plates and plate assemblies, which are resulted from various preloadings and may cause prebuckling deformations before buckling, are included in the analysis. Material nonlinearity and residual stress are also considered. It can be applied to sections with simple or non-simple boundary conditions and arbitrary loading. The method has been applied to investigate the buckling behavior of plates and plate assemblies which are subjected to compression with initial imperfections and residual stresses.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.763-768
• /
• 2000

In this study, the tests were performed on a series of reinforced concrete strip specimens to investigate a cracking behavior of reinforced concrete voided slab bridge. Also, the mid-span deflections, the crack widths and failure mode of reinforced concrete strip specimens were studied. It was found that serviceability of cracking and deflection at reinforced concrete voided slab bridge which were constructed and designed under verifying serviceability as design criteria are lower than common reinforced concrete member. On the basis of the experimental results, it is more reasonable concrete to evaluate crack occurring $f_r=2.0\surd{f_{ck}}$ rather than modulus of rupture of concrete, $f_r=0.8\surd{f_{ck}}$