• Title, Summary, Keyword: Cavity resonator

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Triple-Mode Characteristics of Cylindrical Cavity Loading a Cylindrical Dielectric Resonator

  • Lee, Seung-Mo;Kim, Cha-Man;Park, Jong-Chul;Kim, In-Ryeol;Oh, Soon-Soo
    • 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.

Effect of the Shape of a Guide Grill Above a Resonance Type Sound Absorbing Panel on Intake Flow into a Resonator (공명 흡음판 위 가이드 그릴의 형상이 공진기 흡입 유동에 미치는 영향)

  • Bae, Hyunwoo;Sung, Jaeyoung;Lee, Dong Hoon
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.25 no.3
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    • pp.182-188
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    • 2016
  • This study investigates cavity flows through a guide grill above a resonator. Vortex distributions and intake flows are simulated for various shapes of the guide grill. The flows are assumed to be compressible, unsteady, and turbulent. Numerical simulations are conducted using a large eddy simulation (LES) model. To analyze the effect of the guide grill shape, three cavity lengths (0.2H, 0.6H, and 1.0H) and cavity angles ($30^{\circ}$, $45^{\circ}$ and $60^{\circ}$) are considered based on resonator height (H). The results show that the vortex generated in the resonator by cavity flow increases with cavity length. Thus, the intake flow is minimum at the smallest cavity length and angle. However, when cavity length is equal to resonator height, the intake flow decreases. The maximum intake flow occurs at a cavity angle $45^{\circ}$ at higher cavity lengths owing to the interaction between the vortex in the resonator and intake flow.

X-Band Oscillator Using SIW Cavity Resonator Based on Planar Circuit Technique (평면회로 기법에 의한 SIW Cavity 공진기를 이용한 X-밴드 발진기)

  • Lee, Hyun-Wook;Lee, Il-Woo;Nam, Hee;Lee, Jong-Chul
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.1
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    • pp.68-74
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    • 2008
  • The substrate integrated waveguide (SIW) structure can be approximated as the rectangular waveguide using common dielectric substrate with via-holes. To realize reflection-type resonator, $50-{\omega}$ microstrip line can be used for coupling with the center plane of the cavity. The oscillator is designed to operate at 9.45 GHz using the reflection-type SIW cavity resonator. The phase noise of oscillator shows -98.1dBc/Hz at 100 KHz offset. In experiment, the reflection type SIW cavity resonator improves the loaded quality factor making the low phase noise oscillator possible. Due to the entirely planar structure of this resonator, this technique can also be adequate in oscillator applications for a low cost and low phase noise performance.

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Aperture Coupled Cylindrical Resonator Oscillator (Aperture Coupled 원통형 공동 공진기 발진기)

  • 나인주;이정해
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.2
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    • pp.119-126
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    • 2003
  • In this paper, a cylindrical cavity resonator oscillator with high Q factor is designed and fabricated to improve the phase noise characteristic. A cavity resonator is coupled to oscillating circuit using aperture hole. Measured results show that the cylindrical cavity resonator oscillator (CRO) for Ku-band has less phase noise than the dielectric resonator oscillator (DRO) with the same oscillating circuit. It has output power of +3.92 dBm at the center frequency 13.4015250 GHz and phase noise of -109 dBc/Hz at 100 kHz offset.

Accurate Measurements of the Unloaded Q of a Dielectric-loaded High-Q $TE_{01{\delta}}$ mode Cavity Resonator with HTS Endplates

  • Kwon, H.J.;Hur, Jung;Lee, Sang-Young
    • 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.

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Effect of Gas-Filled Cavity Of! Frequency Response of a Pressure Transducer (기포로 채워진 캐비티가 압력 센서의 주파수 응답 특성에 미치는 영향)

  • Kang, Kwan-Hyoung;Lee, Mu-Yeol;Kim, Young-Gi
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.785-790
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    • 2000
  • The resonant frequency of a gas-filled cylindrical Helmholtz resonator in a liquid is obtained analytically. The equation of motion of the resonator is derived by using the condition of equilibrium of forces acting on the mass in the neck of the resonator. The reaction force on the upper side of the cylinder due to the acceleration of external fluid and sound radiation is obtained by using the analytical results for the baffled circular-piston problem. From the frequency response function of the resonator, a formula to predict the resonant frequency of the resonator is derived. It is shown that the resonant frequency of the Helmholtz resonator significantly decreases due to the cushioning effect of gas inside the cavity. Therefore, when a pressure transducer is to be installed in a pin-hole type mounting method, much care should be paid to remove the gas from the cavity.

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Characteristics of Acoustic Damping Induced by Helmholtz Resonators with Various Geometric Factors in a Model Chamber (모형연소실내에서 헬름홀츠 공명기의 기하학적 형상 인자에 따른 음향 감쇠 특성)

  • Choi, Hyo-Hyun;Park, I-Sun;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.254-257
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    • 2010
  • Acoustic design parameters of a Helmholtz resonator are studied experimentally and numerically for acoustic stability in a model acoustic tube. Acoustic damping is quantified by the amplitude of the fluid velocity in mass-spring-damper system. The length of an orifice, the volume of a cavity, and the diameters of an orifice and a cavity in the resonator are selected as design parameters for tuning of the resonator. It is found that acoustic damping capacity is increased by shorter orifice and longer cavity in the resonator. As the ratio of the orifice diameter to the cavity diameter increases in the resonator, the damping capacity decreases.

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A Comparative Study for the Microwave Surface Resistances of $YBa_2$$Cu_3$$O-{7-$\delta$}$ Films Measured with a Microstrip Resonator and a Inutile-loaded Cavity Resonator (마이크로스트립 공진기와 Rutile-loaded Cavity 공진기로 측정한 $YBa_2$$Cu_3$$O-{7-$\delta$}$박막의 마이크로파 표면저항 비교 연구)

  • O. K. Kwon;H. J. Kwon;Lee, J. H.;Jung Hur;Lee, Sang-Young
    • Progress in Superconductivity
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    • v.2 no.2
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    • pp.86-91
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    • 2001
  • Temperature dependences of the unloaded Q(Q$_{0}$) and the resonant frequency ( $f_{0}$) of YB $a_2$C $u_3$ $O_{7-{\delta}}$ (YBCO) microstrip ring resonators and rutile-loaded cylindrical cavity resonators were measured at low temperatures. Dc magnetron-sputtered YBCO films grown on Ce $O_2$-buffered r-cut sapphire (CbS) substrates were used fur this purpose. The surface resistances ( $R_{s}$) of YBCO films measured by both a microstrip ring resonator and a TE $01\delta$/ mode rutile-loaded cylindrical cavity resonator are compared with each other. It turned out that the values of $R_{s}$ measured by the microstrip resonator technique are comparable to those by the rutile-loaded resonator technique at temperatures lower than ~50 K. However, above 50 K, the $R_{s}$ measured by the microstrip resonator technique appeared higher according to the temperature. Our results show that the current crowding effects near the edge of a microstrip resonator become more significant at temperatures near the critical temperature.emperature.e.e.e.e.e.e.

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A Study on the Phase Noise Improvement of Oscillator using Dielectric-rod loaded Cavity Resonators with HIS End-plates (고온초전도체와 유전체 삽입 공동 공진기를 이용한 발진기의 위상잡음 개선에 관한 연구)

  • Lee, Won-Hui
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.2
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    • pp.174-177
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    • 2009
  • In this paper, an oscillator using dielectric-rod loaded cavity resonators with HTS(High Temperature Superconductor) end-plates was presented. It was operated at X-band. A two port cavity resonator was incorporated into a basic feedback loop oscillator configuration. A rutile loaded cavity resonator with HTS thin film end-plates was used to provide the quality factor between $10^4$ and $10^6$. A parallel feedback oscillator was constructed with a dielectric loaded cavity resonator, an amplifier, and a directional coupler. At 300 K, the experimental results showed the phase noise of -108 dBc/Hz at a 100 kHz offset frequency. At 26 K, the results was -118.8 dBc/Hz at same offset frequency.