• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.3A
• /
• pp.321-327
• /
• 2006

In this paper, when a H-polarized plane wave is incident on the grating consisting of uniform resistive strips, electromagnetic scattering is analyzed using the moment of methods (MoM). The current density of each resistive strip on a grounded dielectric plane is fixed by zero at both edges. To satisfy the condition at both ends of each resistive strip, the induced surface current density is expanded in a series of cosine and sine functions. The scattered electromagnetic fields are expanded in a series of floquet mode functions. The boundary conditions are applied to obtain the unknown current coefficients. According to the variation of the involving parameters such as strip width and spacing and angle of the incident field, numerical simulations are performed by applying the Fourier-Galerkin moment method. The numerical results of the normalized reflected power for resistive strips case for zero and several resistivities are obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.5
• /
• pp.495-503
• /
• 1997

In this paper, the E-polarized electromagnetic scattering problems by a resistive strip grating with tapered resistivity on 3 dielectric layers are analyzed to find out the effects for the tapered resistivity of resistive strip and the relative permittivity and thickness of 3 die- lectric layers by applying the Fourier-Galerkin moment methods. The induced surface current density is expanded in a series of Jacobi-polynomial ${P^{(\chi,\beta)}}_p$(.) of the order $\alpha$= 0 and $\beta$=1 as a kind of orthogonal polyomians, and the tapered resistivity assumes to vary linearly from 0 at one edge to finite resistivity at the other edge. The normalized reflected and transmitted powers are obtained by varying the tapered resistivity and the relative permittivity and thickness of dielectric layers. The sharp variation points are observed when the higher order modes are transferred between propagating and evanescent modes, and in general the local minimum positions occur at less grating period for the more relative permittivity of dielectric layers. It should be noted that the patterns of the normalized reflected and transmitted powers for the tapered resistivity are very much different from those of the uniform resistivity and perfectly conducting cases. The proposed method of this paper cna solve the scattering problems for the tapered resistive, uniform resistive, and PEC strip cases.

• Proceedings of the KAIS Fall Conference
• /
• 2004.06a
• /
• pp.247-249
• /
• 2004

본 논문에서는 격자구조의 유전체에 수직으로 입사된 전자기파의 산란, 투과 특성을 얇은 위상 막 근사화 이론을 이용하여 분석하였다. 위상 막 근사화 이론은 격자구조가 입사되는 전자기파의 위상 변화만을 주는 것으로 간주하는 것으로 이를 이용하여 격자구조를 통과한 직후인 근거리 필드 분포를 TE 모드에서 계산하였다. 기존의 제시된 이론에 비해 비교적 간단하고 빠르게 산란 필드를 분석할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.8
• /
• pp.340-348
• /
• 2003

In this paper, we propose a novel formulation to solve a time-domain combined field integral equation (CFIE) for analyzing the transient electromagnetic scattering response from closed conducting bodies. Instead of the conventional marching-on in time (MOT) technique, tile solution method in this paper is based on the moment method that involves separate spatial and temporal testing procedures. Triangular patch vector functions are used for spatial expansion and testing functions for three-dimensional arbitrarily shaped closed structures. The time-domain unknown coefficient is approximated as a basis function set that is derived from tile Laguerre functions with exponentially decaying functions. These basis functions are also used as the temporal testing. Numerical results computed by the proposed method arc stable without late-time oscillations and agree well with the frequency-domain CFIE solutions.

• Journal of Sensor Science and Technology
• /
• v.33 no.3
• /
• pp.139-146
• /
• 2024

Surface-enhanced Raman scattering (SERS) enables the detection of various types of π-conjugated biological and chemical molecules owing to its exceptional sensitivity in obtaining unique spectra, offering nondestructive classification capabilities for target analytes. Herein, we demonstrate an innovative strategy that provides significant machine learning (ML)-enabled predictive SERS platforms through surface-engineered graphene via complementary hybridization with Au nanoparticles (NPs). The hybridized Au NPs/graphene SERS platforms showed exceptional sensitivity (10^-7 M) due to the collaborative strong correlation between the localized electromagnetic effect and the enhanced chemical bonding reactivity. The chemical and physical properties of the demonstrated SERS platform were systematically investigated using microscopy and spectroscopic analysis. Furthermore, an innovative strategy employing ML is proposed to predict various analytes based on a featured Raman spectral database. Using a customized data-preprocessing algorithm, the feature data for ML were extracted from the Raman peak characteristic information, such as intensity, position, and width, from the SERS spectrum data. Additionally, sophisticated evaluations of various types of ML classification models were conducted using k-fold cross-validation (k = 5), showing 99% prediction accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.7
• /
• pp.722-729
• /
• 2004

To analysis on the degradation of the satellite communication signal due to Asian dust that appeared on Korean peninsula during March and April 2004, EIRPs of L, S, C, Ku and Ka frequency bands of the downlink of satellite communication link were measured by Satellite Signal Monitoring Center located in Icheon, Korea. The measured EIRP values were compared to the total dust density and dust particle distribution that were measured using PM 10 and OPC by the Korea Meteorological Administration, and the possible correlation between three sets data were analyzed.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.173-176
• /
• 2002

An efficient design method for E-plane waveguide bandpass filter has been developed. The analysis method for E-plane discontinuities with finite length is based on Generalized Scattering Matrix (GSM) method. Furthermore, the design portion is based on the filter synthesis method. Waveguide bandpass filters designed with this method have been fabricated and measured. Excellent agreements with design have been obtained

• Journal of electromagnetic engineering and science
• /
• v.13 no.3
• /
• pp.158-164
• /
• 2013

This paper expands a previously proposed optimized higher order (2, 4) finite-difference time-domain scheme (H(2, 4) scheme) for use with lossy material. A low dispersion error is obtained by introducing a weighting factor and two scaling factors. The weighting factor creates isotropic dispersion, and the two scaling factors dramatically reduce the numerical dispersion error at an operating frequency. In addition, the results confirm that the proposed scheme performs better than the H(2, 4) scheme for wideband analysis. Lastly, the validity of the proposed scheme is verified by calculating a scattering problem of a lossy circular dielectric cylinder.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.3
• /
• pp.464-473
• /
• 2000

The method is presented which predicts voltage waveforms at each nodes inter-connected arbitrarily on the coupled transmission lines by extracting the node connection condition to be included in the modal telegrapher's equation, hence analyzing the mechanism of waveform propagation on transmission lines. It is shown that it is also possible to analyze efficiently the coupled nonuniform lines. And then the nonuniformity of coupled lines is demonstrated for suppressing the crosstalk spikes using the one-dimensional inverse-scattering control theory. The predicted waveforms by presented method are analyzed and verified by comparison with those by the generalized S-parameter technique.