• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1420-1427
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• 2000

We described a method to obtain electromagnetic solution and resonant frequencies in dielectric-disc loaded cylindrical cavity resonators. Resonant frequency of dielectric-disc loaded cylindrical cavity resonators is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As increasing to height of cavity, we compare the calculated resonant frequency with experimental frequency. The calculated results well agree with the experimental ones. The error between them is 0.2% or 1.6% for the case of the top plate is close to or far from concentric dielectric-disc, respectively.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.306-310
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• 2002

본 논문에서는 기존의 혼 안테나에 Dielectric rod를 삽입하는 구조를 사용하였다. 입력구조는 Rectangular Waveguide Feed에 Cone을 접목시키는 형태로 구현되었으며 기존의 E-Plane taper구조보다 특성이 양호하며 소형화를 구현해냈다. 제작된 안테나의 중심주파수는 37GHz이며 정재파비 특성 또한 양호하다. 여러 Feeding 구조 중 Bandwidth를 좀더 확장할 수 있는 구조에 초점을 맞추어 대역폭은 13%이상을 구현했으며 시뮬레이션 툴은 Ansoft HFSS V7.0으로 최적화한 후 제작 및 측정하였다. 또한 사용된 Dielectric rod의 제질은 Teflon(ETFE, $\varepsilon$$_{r}$=2.03)을 사용하였다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.9
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• pp.8-14
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• 1992

The radiation pattern of a rectangular-grid array antenna consisted of rectangular waveguides is represented by multiplication of its element and array factors. Calculated radiation patterns for excitation of TES110T mode inside the waveguides suffer from the blindness at a particular direction on E-plane. Numerical simulations show that the blindness can be removed by inserting dielectric plug inside the waveguides or covering dielectric sheath in front of the waveguides.

• Macromolecular Research
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• v.11 no.4
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• pp.256-259
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• 2003

Measurements of Young's modulus, dielectric loss and a.c. conductivity have been carried out on EPDM rubber samples loaded with different concentrations of $CrCl_3$ (0,2,4 and 6 phr). The values of Young's modulus was found to be linearly dependent on the $CrCl_3$ content. Variation of the dielectric loss with temperature showed that $CrCl_3$ may act as plasticizer. However, at higher frequencies the dielectric loss was found to be independent of frequency and the rubber samples may behave as non-polar dielectric. Investigations of the a.c conductivity suggested that the conduction in these rubber samples can be described by small polaron tunneling. In addition, conductivity was found to increase with $CrCl_3$ content.

• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.1-4
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• 2011

In this letter, we propose a novel tag antenna that has low performance degradation with nearby dielectric material. We obtained a stable reading performance and a broad matching bandwidth on nearby dielectric materials by employing a T-matching network with thick line width and capacitively slot-loaded arms. We then built the proposed antenna and measured the tag sensitivity to examine the reading characteristics with nearby dielectric materials. The measured results clearly demonstrate stable tag sensitivity with various nearby dielectric materials, such as foam, acrylic-plastic, glass, and ceramic plates. To more closely observe the antenna characteristics with nearby dielectric materials, we also examined the impedance variation and surface current distribution with respect to the dielectric constant of nearby target objects, which ranged from $1{\times}{\varepsilon}_0$ to $16{\times}{\varepsilon}_0$.

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.60-60
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• 2004

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.71-80
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• 1996

Sattering problem of electromagnetic waves by periodic strip grating with two dielectrics over a ground plane in case of oblique incidence and arbitrary polarization is analyzed by the vector floquet mode expansion method and the moment mehtod from the viewpoint of soft and hard boundary value problem. To confirm proposed analysis methods, we examine the solution convergence for the scattering problem. And some numerical results of artificially soft and hard surfaces using the structure filled with single dielectric slab between periodic strip grating and gorund plane is compared with previous results. Some interesting results for soft and hard surfaces using periodic strips loaded with two layered dielectric slabs over a ground plane are given.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.7-12
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• 1990

A rigorous analysis of the scattering problem by the perfectly conducting strip loaded with a dielectric cylinder of different permittivity is presented. By introducing auxiliary electromagnetic fields and applying the reciprocity theorem, integral equations for the unknown electric field are derived. These integral equations are transformed into an equivalent matrix equation of infinite order with proper boundary conditions. By calculating inverse matrix of unknown coefficients from this equation, scattered electric fields are determined. In particular case of the dielectric with the same permittivity, the results of this paper correspond to well-known results.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.67-71
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• 2003

In this paper, frequency modulated(FM) reflectometry is proposed to measure group velocity of microwave transmission line Various microwave transmission lines such as periodically loaded conducting posts in a waveguide and nonradiative dielectric(NRD) guide are adopted to measure their group velocity The result compared with that from network analyzer shows good agreement, indicating the validity of our measurement method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.630-636
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• 2016

In this paper, a novel triple-mode cavity structure, designed for compactness and operating at 850 MHz, is analyzed. A cylindrical dielectric resonator is loaded into a metallic cylindrical cavity. Previous study has been focused on the analysis of the cylindrical dielectric resonator, but in this paper, the effect of the cylindrical metallic cavity has been analyzed. Enclosing the dielectric resonator inside the metallic cavity increases the resonant frequency of the dielectric resonator; however, this increases the quality factor and introduces the possibility of installing coupling screws. The principle of generation of triple-mode was investigated by parametric analysis. The generated triple-mode is TE011 mode and two orthogonally generated HEM121 modes. By adjusting the radius of the dielectric resonator, the height of the dielectric resonator, or the radius of the cylindrical metallic cavity, three modes could be coincided. However, the height of the metallic cavity keeps three modes separated. The mode characteristics of the proposed cavity are analyzed using a full-wave electromagnetic (EM) simulation. The proposed triple-mode cavity could be developed to triple-mode filter using a coupling screw, and the commercial application for the miniaturized filter below 1 GHz could be expected.