• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1738-1745
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• 2015

Radiation characteristics of a probe-fed rectangular microstrip patch antenna printed on a finite grounded high permittivity substrate are investigated systematically for various square grounded dielectric substrate sizes with several thicknesses and dielectric constants by experiment and full wave simulation. The effect of the substrate size on the radiation characteristics of a rectangular patch antenna is mainly determined by the effective dielectric constant of surface waves on a grounded dielectric substrate. As the effective dielectric constant of surface waves increases, the substrate sizes for the maximum broadside gain and the required onset for a large magnitude of squint angle decrease, while the variations of the broadside gain, the front-to-back ratio, and the magnitude of squint angle versus the substrate size increase due to the increase of the power of the surface wave.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.11
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• pp.1-7
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• 2000

Surface wave scattering by periodic grooves of arbitrary profile in a grounded dielectric slab is investigated for the TE surface wave incidence. Both the finite and infinite periodic geometries are considered. The former case is analyzed by using of hybrid FEM/MOM and the latter by using of full MOM procedure. Some numerical results for the reflected and transmitted powers in a grounded dielectric slab, radiation power into the free space, and radiation patterns in case of finite structure and for the dispersion diagram in case of infinite structure are presented. And some descriptions on the relationship between the finite and infinite structure such as the maximum beam angle are given.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.6
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• pp.26-34
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• 2010

The mutual coupling of a pair of microstrip patch antennas on a finite grounded dielectric substrate is influenced by the diffracted field of surface waves from the edges of a substrate. The effective dielectric constant of a grounded dielectric substrate determines the distance between the antenna center and the edge of a substrate to obtain the minimum mutual coupling between a pair of microstrip patch antennas. The optimum substrate size with the minimum mutual coupling is easily calculated using the image method. The optimum substrate sizes using the linage method are in good agreement with the results obtained by the full wave simulation.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.147-155
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• 2005

In this paper, we propose that three uniform coplanar waveguides(CPWs), such as a conventional, finite grounded(FG), and grounded(G) CPWs, can be coupled with a $TE_{01{\delta}}$ mode dielectric resonator(DR) for a parallel resonant characteristic as a microstrip line coupled with the DR. Coupling characteristics have been investigated by placing the DR on a dielectric support above the CPWs and by moving the DR away from the center of a slot of the CPWs to the ground plane. FEM simulation(HFSS) results in terms of S-parameters agree well with measurement results. Finally, unloaded Q values of the DR coupled with the three uniform CPWs are compared with those of the DR coupled with a microstrip line. The comparison shows that the DR coupled with the three CPWs has higher unloaded Qs than that coupled with a microstrip line and that the GCPW case has the highest unloaded Qs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.92-99
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• 2011

Effect of a finite grounded substrate on mutual coupling characteristics of a 2-element array antenna using inductor loaded patch antennas is investigated. The mutual coupling characteristics of a 2-element array antenna using inductor loaded patch antennas positioned along the E-plane are compared with those positioned along the H-plane. The magnitude of mutual coupling is very small and the distance between the center of element and the substrate edge on the E-plane for the minimum mutual coupling is similar regardless of the direction at which antenna elements are positioned in the case of a 2-element array antenna using inductor loaded patch antennas.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.631-636
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• 2010

Gas-insulated transmission lines (GITL) are valued as technological solutions in hydro-power stations due to their enormous power handling capabilities. The performance of GITL is a function of the size of metallic particles inside the gas-insulated chamber. Electrostatic field (E-field) enhancement is a common phenomenon in gas-insulated lines due to these metallic particles. In this study, the E-field enhancement factor is calculated by considering metallic particles at various locations in the gas-insulated line/bus section, such as high-tension (HT) conductor, high-voltage shields, support insulator, and inner surface of grounded enclosure. For this purpose, a two-dimensional model based on finite element (FE) method is developed. The length of the metallic particle is in the range of 1 to 10 mm while the diameter is between 1 to 3 mm. E-field enhancement is also computed for various particle configurations of the gas-insulated system, with focus on dielectric coating made of epoxy on HT conductor and inner surface of grounded enclosure.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.320-324
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• 2015

Mutual coupling between antenna elements of a linear microstrip patch antenna array positioned along the H-plane including the effect of edge reflections is investigated. Simple formulas are presented for the estimation of the grounded dielectric substrate size with minimum mutual coupling. The substrate sizes calculated by these formulas are in good agreement with those obtained by the full-wave simulation and experimental measurement. The substrate size with minimum mutual coupling is a function of the effective dielectric constant for surface waves and the distance between the antenna centers. The substrate size with minimum mutual coupling decreases as the effective dielectric constant for surface waves on a finite grounded dielectric substrate increases.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.27-34
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• 2015

Dynamic vibration absorbers are widely used in machinery, buildings, and structures, including bridges. Two cases of their usage are considered in this paper. One is a simply supported beam subjected to either a moving force or a sequence of moving forces, which simulates a train-bridge interaction problem. The other is a case where a primary system is mounted on a base that is not grounded and is excited by an external force. The conditions that the dynamic vibration absorbers must meet in these cases are found and compared to those for usual cases where bases of primary systems are grounded.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.83-88
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• 2006

In this paper, we propose a new cross bar embedded structure for improvement of attenuation characteristics along the different lossy media. A general characterization procedure based on the extraction of the characteristic impedance and propagation constant for analyzing a single MIS(Metal-Insulator-Semiconductor) transmission line used and an analysis for a new substrate shielding MIS structure consisting of grounded crossbars at the interface between Si and Sio2 layer using the Finite-Difference Time-Domain(FDTD) technique is used. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded cross bar lines over time-domain signal has been examined. The extracted, distributed frequency-dependent transmission line parameters as well as the line voltages and currents, and also corresponding equivalent circuit parameters have been examined as function of frequency. It is shown that the quality factor of the transmission line can be improved without significant changes in the characteristic impedance and effective dielectric constant.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.543-548
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• 2011

In this paper, H-polarized electromagnetic scattering problems by a resistive strip grating over a grounded dielectric plane according to the strip width and grating period, the relative permittivity and thickness of a dielectric layer, and incident angles of a TE (transverse electric) plane wave are analyzed by applying the FGMM (Fourier-Galerkin Moment Method). The tapered resistivity of resistive strips in this paper varies from finite resistivity at one edge to zero resistivity at the other edge, then the induced surface current density on the resistive strip is expanded in a series of Jacobi polynomials of the order ${\alpha}=1$, ${\beta}=0$ as a kind of orthogonal polynomials. The numerical results of the normalized reflected power show in good agreement with those of existing papers.