• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.87-92
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• 2016

In this paper, the solutions of TE(transverse electric) scattering problems by a conductive strip grating over two dielectric layers are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic field. 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 conductive boundary condition apply to analysis of conducting strip. The most normalized reflected and transmitted powers having a sharp variations are scattered in direction of the other angles except incident angle. The numerical results for the normalized reflected and transmitted powers are analyzed by according as the width and spacing of conductive strip, incident angles, and the relative permittivity and thickness of the two dielectric layers. To confirm the validity of this paper, the numerical results of presented structure are shown in good agreement compared to those of the existing papers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.83-88
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• 2017

In this paper, TE(transverse electric) scattering problems by a conductive strip grating between a double 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, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the conductive boundary condition is applied to analysis of the conductive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of conductive strip, the relative permittivity and thickness of the double dielectric layers, and incident angles. The most normalized reflected powers of the sharp variations in minimum values are scattered in direction of the other angles except incident angle. 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 Institute of Electronics Engineers of Korea TC
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• v.40 no.9
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• pp.384-391
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• 2003

The wideband annular ring slot antenna with concentric radiating structure and low impedance feedline has been presented. This antenna has been analyzed in compensation for FR-4 substrate with relative permittivity 4.3 and thickness 1 mm. As the measured 10 dB impedance bandwidth of the proposed antenna is 127.2%(2.17∼9.76 GHz), its bandwidth is much broader than maximum 82% bandwidth of a conventional annular ring slot antenna. Experimental results from 2 to 10 GHz are shown to be in good agreement with the simulation. And this antenna has a high gain above 4 dBi from 2 GHz to 10 GHz as well as a 24% size reduction and 42% area reduction than a circular slot antenna.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.27-35
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• 1999

A radius of ring resonator is determined by the resonant frequency. Resonant frequencies of resonators with the circumference which is integer times of wave length are not same the expected. In this paper, we suggest the design method of a ring resonator with coupling gap, which has the resonant frequency of desire. The equation which can make reduction of the radius of the resonators depending on the gap space is derived by the method of transmission line analysis. The criterion is suggested to determine the radius of the resonator in accordance with relative permittivity. A ring resonator by the proposed method is as small as one-third of basic ring in size and it has the resonant frequency of desire. T-type coupling line is designed to obtain large attenuation of $S_{11}$ at pass-band. These coupling line capacitances are very lower than the gap capacitances, it does not affect the resonant frequency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.155-161
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• 2007

This paper presents the design simulation, implementation, and measurement of a miniaturized PCS / Satellite DMB dual-band stacked mompole antenna with a parasitic patch for mobile communication terminals. A stacked helix is realized by using a via hole with height of 0.4 mm and a diameter of 0.35 mm to connect upper- and lower-layer helix sections for a reduction of the dimensions of the antenna. In addition the stacked helix chip antenna is interleaved with a parasitic patch to achieve two different radiation modes. The ratio of the first frequency and the second frequency vary with the geometrical parameter of the parasitic patch. The fabricated antenna uses FR-4 substrate with a relative permittivity of 4.2. Its dimensions are $15.5{\times}7.6{\times}0.4 mm^3$. The measured impedance bandwidths (VSWR<2) are 240 and 250 MHz at the operating frequencies, respectively.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.193-197
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• 2009

In this paper, the EM wave absorber was designed and fabricated for improvement of Wireless LAN environment at 2.4 GHz. We fabricated several samples in different composition ratios of Sendust and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Sendust and CPE was searched as 80: 20 wt.% by experiments and simulation Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the EM wave absorber was fabricated based on simulated data. Simulated and measured results agreed well. As a result, the developed EM wave absorber with thickness of 3.25 mm has absorption ability of 19 dB at 2.4 GHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1724-1729
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• 2015

Chlorosulfonated polyethylene (CSPE) was not flooded seawater and flooded seawater & freshwater for 5 days, respectively, and these samples are referred to as BSF(before seawater flooding) and ASFF(after seawater & freshwater flooding), respectively. The apparent density, dissipation factor, relative permittivity, melting temperature, dielectric breakdown time and increased time of applied voltage are higher than those of BSF, but the insulating resistance, dielectric strength, percent elongation and glass transition temperature of ASFF are lower than those of BSF. The differential temperature of those is $0.026{\sim}0.028(^{\circ}C)$ after AC and DC voltage is applied to ASFF, respectively, and the differential temperature of those is $0.013{\sim}0.037(^{\circ}C)$ after AC and DC voltage is applied to BSF, respectively. In the case AC and DC voltage is applied to ASFF as well as BSF, the variations in temperature of AC voltage are higher than those of DC voltage. It is investigated that dielectric loss due to dissipation factor ($tan{\delta}$) is related to electric dipole conduction current. It is certain that the ionic (electron or hole) leakage current was increased by conducting ions such as $Na^+$, $Cl^-$, $Mg^{2+}$, $SO_4^{2-}$, $Ca^{2+}$ and $K^+$, those are related to cured atoms of O and S that relatively increased after seawater flooding.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.84-93
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• 2016

The signal characteristic of radar wave on concrete decks is determined by the attenuation of the radar due to the conversion of EM(Electromagnetic) energy to thermal energy through electrical conduction, dielectric relaxation, scattering, and geometric spreading. In this study, it is found that the attenuation of radar signal received on top rebars in bare deck concrete with 2 way travel time shows a general decreasing linear trend because of its same relative permittivity and conductivity. The radar signal after depth-normalization, can then be interpreted as being principally influenced by the content of chlorides penetrating cover concrete, which caused corrosion of rebars in bridge decks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.6
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• pp.740-747
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• 2019

In this paper, an antenna applicable to WLAN and WiMAX frequency bands is designed, fabricated, and measured. The proposed antenna is designed to have two branch strip line in the patch plane and a rectangular slit in the ground plane based on microstrip feeding for triple band characteristics and added a vertical strip in the ground plane to enhance impedance bandwidth characteristics. The proposed antenna is designed on a substrate with a relative permittivity of 4.4, a thickness of 1.0 mm, and has a size of $18.0mm(W1){\times}37.3mm$ (L4+L5+L7). From the fabricated and measured results, impedance bandwidths of 480 MHz (2.32 to 2.80 GHz) for 2.4/2.5 GHz band, 810 MHz (3.22 to 4.03 GHz) for 3.5 GHz band, and 1,820 MHz (5.05 to 6.87 GHz) for 5.0 GHz band were obtained based on the impedance bandwidth. Measured 3D pattern and gains are displayed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.47-52
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• 2019

In this paper, TE(transverse electric) scattering problems by a conductive strip grating between a double dielectric layer are analyzed by applying the FGMM(Fourier-Galerkin moment method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, and the conductive boundary condition is applied to analysis of the conductive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of conductive strip, the relative permittivity and thickness of the double dielectric layers, and incident angles. Generally, as the value of the dielectric constant increases, the reflected power increases and the transmitted power decreases, respectively. As the dielectric constant increases, the current density induced in the strip increases as it goes to both strip ends. The numerical results for the presented structure of this paper are shown in good agreement compared to those of the existing papers.