• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.906-911
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• 2004

In this paper, a VCDRO(Voltage Control Dielectric Resonator Oscillator) applied to FMCW(Frequency Modulated Continuous Wave)Radar as stable source is implemented and constructed with a MESFET(Metal-semiconductor Field-Effect Transistor) for low noise, a dielectric resonate. of high frequency selectivity, and high Q varator diode to obtain a good phase noise performance and stable sweep characteristics. The designed circuits is simulated thrash harmonic balance simulation technique to provide the optimum performance. The measured result of a fabricated VCDRO shows that output is 2.22㏈m at 12.05GHz, harmonic suppression -30㏈c, phase noise -130㏈c at 100KHz offset, and sweep range of varator diode $\pm$18.7MHz, respectively. This oscillator will be available to FMCW Radar.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1527-1529
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• 2002

본 논문은 저손실 소형 대역통과 여파기인 기지국용 RF/Microwave 수동소자의 다중 공진 모드(Multi-Mode)에 관한 연구로 한개의 유전체 공진기(Dielectric Resonator)로 두개의 공진 모드(Dual-Mode)를 형성하고 그의 결합량을 조절하여 대역통과 여파기를 설계 및 제작하고, 기지국용 Dual-Mode 대역통과 여파기의 소형화, 경량화를 50%이상 향상시켜 양질의 Dual-Mode 공진 특성을 관찰하였다.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1615-1617
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• 2004

5 mol% $BaWO_4$를 첨가시켜 합성한 Ba$(Mg_{1/3}Ta_{2/3})O_3$를 이용하여 비방사유전세선로에 삽입되는 세라믹스 공진기를 제자하고 기존의 $MgTiO_3-CaTiO_3$계 세라믹스 공진기와 공진특성을 비교하여 그 특성을 고찰하였다. 그 결과 BMT 세라믹스는 기존의 $MgTiO_3-CaTiO_3$계 세라믹스보다 품질계수가 2배 이상 크게 높게 측정되었고, 측정 사진의 관찰 결과 전파차단성도 우수할 것으로 예상되기 때문에 BMT가 비방사유 전체선로에 삽입되는 유전체 공진기 재료로서 적용될 경우 우수한 공진특성을 발휘할 것으로 판단된다.

• Progress in Superconductivity
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• v.13 no.2
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• pp.97-104
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• 2011

In the dielectric resonator method, which has been widely used for measuring the microwave surface resistance of superconductors, accuracies in the geometrical factors (G-factors) affect the uncertainty in the measured surface resistance. We compare the G-factors of short-ended sapphire resonator as obtained by using field analysis with those by using computer simulations: The former is obtained by using the analytic expressions for the electric and the magnetic field components inside the resonator, and the latter by using computer software. The G-factors as obtained by using the latter appear to be closer to those obtained by using the former as the resonator space is divided into larger number of sub-space, i.e., a tighter mesh, with a difference of ~8 % observed for a mesh of 14400 sub-spaces reduced to ~2 % for 114996 sub-spaces. Variations in the relative uncertainty in the surface resistance of typical $YBa_2Cu_3O_{7-\delta}$ superconductor films with those in the G-factors are studied, which provides an upper limit of the relative uncertainty in the G-factors required for realizing the target uncertainty in the surface resistance. These results could be useful in estimating the optimum number of meshes for obtaining the G-factors through computer simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.805-814
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• 1999

In this paper, elliptic function bandpass filters using ceramic coaxial resonators are designed. Since elliptic function filters have better performance of frequency selectivity than those based on Butterworth or Chebyshev, therefore it is possible to make better use of limited frequency resources. Elliptic function bandpass filters using ceramic coaxial resonators are designed for reducing it's size, weight, cost and for easy manufacturing and tuning. From measurements, an accurate resonator model is obtained and the coupling coefficient values are extracted. Based on these results, elliptic function bandpass filters are designed. The experimental results have shown that the 8th order elliptic function filter of 959 MHz center frequency with 28 MHz bandwidth using coaxial ceramic resonators have about more tan 17 dB return loss, 5 dB insertion loss, more than 20 dB attenuation at $f_c\pm$5 MHz.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.6
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• pp.396-396
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• 2000

Three-Dimensional FDTD method is applied to analyze the dielectric resonator coupled with two microstrip lines. We model accurately the curved surface using Noriaki model. The frequency resolution is 106.46 MHz by the conventional FFT However it is not sufficient for determining its resonant frequency. So we introduce the Pad approximation and Stoer-Bulirsch method in order to have the high frequency resolution degree, 1.00 MHz. All results are compared with the measured data. As a result, we acquire the very precise result through the Pad approximation. And sinusoidal wave is applied. From the plot of the electric and magnetic field distribution, it is shown that the resonant mode is $TE_{01{\delta}}$ mode.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.6
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• pp.36-43
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• 2000

Three-Dimensional FDTD method is applied to analyze the dielectric resonator coupled with two microstrip lines. We model accurately the curved surface using Noriaki model. The frequency resolution is 106.46 MHz by the conventional FFT However it is not sufficient for determining its resonant frequency. So we introduce the Pad approximation and Stoer-Bulirsch method in order to have the high frequency resolution degree, 1.00 MHz. All results are compared with the measured data. As a result, we acquire the very precise result through the Pad approximation. And sinusoidal wave is applied. From the plot of the electric and magnetic field distribution, it is shown that the resonant mode is TE$_{01{\delta}}$ mode.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9B
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• pp.1196-1202
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• 2001

본 논문에서는 대역통과 필터특성을 위해 통과대역의 상단과 하단의 저지대역에서 감쇄극을 갖는 두 종류의 새로운 마이크로스트립 구조를 제안한다. 이 구조는 TEM모드의 유전체 공진기를 마이크로스트립선로에 용량성 또는 유도성의 병렬 포스트와 연결하여 구성된다. 제안한 구조에 대한 등가회로를 추출하였다. 이 구조의 S-파라미터를 실험과 등가회로 시뮬레이션으로 구하였고, 그리고 유도성포스트의 경우는 3D-FDTD 계산을 추가하여 서로를 비교하였는데 등가회로 모델이 이들 결과와 매우 잘 일치하였다.

• 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 Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.34-40
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• 2004

The PLDRO(Phase-Locked Dielectric Resonator Oscillator) with low phase noise is designed for X-band. The phase of VCDRO(Voltage Controlled Dielectric Resonator Oscillator) is locked to that of a high stable reference oscillator by using a SPD(Sampling Phase Detector) to improve phase noise performance in the loop bandwidth. And, the VCDRO is implemented using a high impedance inverter coupled with dielectric resonator to improve the phase noise performance out of the loop bandwidth. This PLDRO exhibits the harmonic rejection characteristics of 51.67㏈c and requires below 1.95W. The phase noise characteristics are performed as -107.17㏈c/Hz at 10KHz offset frequency and -113.0㏈c/Hz at 100KHz offset frequency, respectively, at ambient. And the output power of 13.0㏈m${\pm}$0.33㏈ is measured over the temperature range of $-20 ∼ +70^{\circ}C$ .