• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.245-248
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• 1997

The dielectric resonators(DRs) with dielectric properties are widely used in microwave integrated circuit(MICs) and monolithic microwave integrated circuits(MMICS). The variational method as numerical simulation scheme would be applied to calculate the resonant frequencies(fr) and Q-factors of microwave dielectric resonators. The dielectric resonator with a cylindrical “puck” structure of high dielectric material is modeled in this simulation. The parameters, such as the diameter, the height, and the dielectric constant of dielectric resonator, would determine the resonant frequency and the Q-factor. The relationship between these parameters would effect each other to evaluate the approximate resonant frequency. This simulation method by the variational formula is very effective to calculate fr, and Q-factor. in high frequency microwave dielectric resonator The error rate of the simulation results and the measured results would be considered to design the microwave dielectric resonators.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.21-25
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• 1989

Theory and experimental results are presented to show the possibility of using a dielectric rod resonator method for characterizing dielectric materials at microwave frequency. The measuring structure is a resonator made up of a cylindrical dielectric rod placed between two parallel conducting plates. In this system, the TE$\_$011/ mode frequency was adapted to minimize the effect of the air-gap between the rod and the conducting plates. The dielectric properties are computed from the resonance frequencies, structure dimensions and 3-dB bandwidth.

• Journal of Radiation Protection and Research
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• v.42 no.1
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• pp.21-25
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• 2017

Background: We are developing L-band and S-band microwave dielectric absorption systems aiming novel dosimetry using DNAs, such as plasmid DNA and genomic DNA, and microwave technology. Materials and Methods: Each system is composed of a cavity resonator, analog signal generator, circulator, power meter, and oscilloscope. Since the cavity resonator is sensitive to temperature change, we have made great efforts to prevent the fluctuation of temperature. We have developed software for controlling and measurement. Results and Discussion: By using this system, we can measure the resonance frequency, f, and ${\Delta}Q$ (Q is a dimensionless parameter that describes how under-damped an oscillator or resonator is, and characterizes a resonator's bandwidth relative to its center frequency) within about 3 minutes with high accuracy. Conclusion: This system will be expected to be applicable to DNAs evaluations and to novel dosimetric system.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.492-499
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• 1997

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.10-15
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• 1990

Theory and experimental results of measuring the microwave dielectric characteristics of low-loss materials by using dielectric rod resonator method are presented. The $TE_{011}$ mode resonance frequency was adapted to minimize the effect of the air gap between the rod and the conducting plates. The dielectric properties were computed from the resonance frequency, sample geometry and 3 dB bandwidth. The error of measurements was within ${\pm}3{\%}$ for dielectric constant and was within ${\pm}12{\%}$ for dielectric loss.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.239-244
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• 1997

A hair-pin shaped microstrip-line resonator and a dielectric resonator for injection-locked oscillators have been designed and fabricated for the comparative studying of their characteristics. In general, a commonly used dielectric resonator shows lower phase noise value than hair-pin resonator in the free-running mode. In the injection-locked mode, however, a hair-pin resonator is superior to the dielectric resonator; the wider tuning range, the 22% improved locking bandwidth, the lower noise effect, the short term stability, and the higher power level. The planar structure of a hair-pin shaped microstrip-line resonator will be easily applied to monolithic microwave integrated circuits.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.171-176
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• 1997

A hair-pin shaped microstrip-line resonator and dielectric resonator for injection-locked oscillators have been designed and fabricated for the comparative studying of their performances. In general, a commonly used dielectric resonator shows lower phase noise value than hair-pin resonator in the free-running mode. In the injection-locked mode, however, a hair-pin resonator is superior to the dielectric resonator, the wider tuning range, the 22% improved locking bandwidth, the lower noise effect, the short term stability, and the higher power level. The planar structure of a hair-pin shaped microstrip-line resonator will be easily applied to monolithic microwave integrated circuits.

• Progress in Superconductivity
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• v.1 no.1
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• pp.36-41
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• 1999

Methods for mode identification and accurate measurements of the unloaded Q ($Q_0$) of a dielectric-loaded $TE_{01{\delta}}$ mode cavity resonator with HTS endplates are proposed. A resonator with a sapphire rod and $YBa_2Cu_3O_{7-x}$(YBCO) endplates was prepared and its microwave properties were studied at temperatures above 30 K. The $TE_{01{\delta}}$ mode $Q_0$ of the resonator, designed to work as a tunable resonator with variations in the gap distance (s) between the sapphire rod and the top YBCO, was more than 1000000 at s = 0 mm and at 30 K with the resonant frequency of 19.56 GHz. The $TE_{01{\delta}}$ mode $Q_0$ decreases as s increases for s < 2 mm until mode couplings between the $TE_{01{\delta}}$ mode and other modes appeared at s = 2 mm. Significant dependence of the $TE_{01{\delta}}$ mode $Q_0$ on the input and output coupling constants was also observed. Applications of the open-ended $TE_{01{\delta}}$ mode cavity resonator for a tunable resonator with a very high Q as well as a characterization tool for the surface resistance measurements of HTS films are described.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.756-760
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• 2007

The $(1-x)Mg_4Ta_2O_9-xwt%TiO_2\;(x=5\sim20)$ microwave dielectric ceramics were prepared by solid-state reaction method and sintered at $1450^{\circ}C$. According to the X-ray diffraction data, the $Mg_4Ta_2O_9-xwt%TiO_2$ ceramics had main phase of $Mg_4Ta_2O_9$ and $MgTi_2O_5$ peaks were added by increasing of $TiO_2$ addition. Microwave dielectric properties of the $Mg_4Ta_2O_9-xwt%TiO_2$ ceramics were influenced by $MgTi_2O_5$ phase and properties of $TiO_2$. There was a little decrement of the quality factor from 116,800GHz of pure $Mg_4Ta_2O_9$ to 100,100GHz of 15wt% $TiO_2$ added one. But there was excellent improvement in temperature coefficient of the resonant frequency (TCRF) by addition of 15wt% $TiO_2$. The dielectric constant quality factor and TCRF of the $Mg_4Ta_2O_9-xwt%TiO_2$ ceramics sintered at $1450^{\circ}C$ were $13.08\sim16.41,\;45,000\sim165,410GHz,\;-24.82\sim+3.88ppm/^{\circ}C$, respectively, depending on the value of x. Simulated dielectric resonator (DR) with $Mg_4Ta_2O_9-15wt%TiO_2$ ceramics had the operating frequency of 11.97GHz and $S_{2,1}$ of -35.034dB.

• ETRI Journal
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• v.23 no.4
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• pp.199-201
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• 2001

The phase noise reduction in a configuration of the HEMT oscillator with a dielectric resonator coupled by a quarter-wavelength impedance inverter is investigated. Two HEMT oscillators for a satellite payload system are manufactured in the same configuration except for the coupling configuration of the dielectric resonator (DR) in order to empirically demonstrate the phase noise reduction. Experimental result shows that a phase noise reduction by 14 dB can be enhanced by increasing the characteristic impedance of a coupling microstrip impedance inverter.