• Title/Summary/Keyword: Parallel-Plate Resonance

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A Study on the Sound Absorptive Characteristics and Performance of Parallel Perforated Plate Systems (병렬 다공판 시스템의 흡음특성과 성능에 관한 연구)

  • Hong, Byung-Kuk;Song, Hwa-Young;Seo, Seong-Won;Lee, Dong-Hoon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9 s.102
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    • pp.1003-1008
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    • 2005
  • The acoustic absorption of a multiple layer perforated plate system is very good near the resonance frequency region, while it has been regarded as a demerit that its frequency bandwidth is considerably narrow. In order to overcome such a demerit, the parallel perforated plates with different porosities are proposed. The sound absorption of such system composed of a parallel perforated plate is calculated by an equivalent electroatoustic circuit approach and validated by comparing the calculated absorption coefficients with those measured by the two-microphone impedance tube method. The sound absorptive characteristics and performance of parallel perforated plate systems are discussed from a standpoint of frequency bandwidth related with sound absorption.

A Study on the Characteristics of a Piezoelectric Ceramic Transformer with divided Electrodes (전극분할형 압전변압기의 특성에 관한 연구)

  • 허두오;강태구;조철환;이해민;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.270-273
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    • 1996
  • This paper describes a type of piezoelectric transformer with improved design principles. It consists of a thin rectangular piezoelectric ceramic plate having two input electrodes and one output electrode. The length of each input and output electrode is nearly one third of that of piezoelectric transformer itself. In the driving section, the ceramic plate is poled in the thickness direction reversely with each other, and has electrodes on both main faces. The electric input near its fundamental resonance frequency is applied to the driving section in parallel and the output voltage from the generating section is connected to the resistor load. Its equivalent circuit is derived from the Mason\`s model. The frequency characteristics near the resonance frequency under no load have been investigated. Moreover, using this piezoelectric transformer we measured the LCD backlight characteristics.

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Design of Power Plane for Suppressing Spurious Resonances in High Speed PCBs

  • Oh Seung-Seok;Kim Jung-Min;Yook Jong-Gwan
    • Journal of electromagnetic engineering and science
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    • v.6 no.1
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    • pp.62-70
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    • 2006
  • This paper presents a new power plane design method incorporating a single geometry derived from a unit cell of photonic bandgap(PBG) structure. This method yields constantly wide suppression of parallel plate resonances from 0.9 GHz to 4.2 GHz and is very efficient to eliminate PCB resonances in a specified frequency region to provide effective suppression of simultaneous switching noise(SSN). It is shown that with only two cells the propagation of unwanted high frequency signals is effectively suppressed, while it could provide continuous return signal path. The measured results agree very well with theoretically predicted ones, and confirm that proposed method is effective for reducing EMI, with measured near-field distribution. The proposed topology is suitable for design of high speed digital system.

Microwave Properties of HTS Parallel-Plate Sapphire Resonators Designed for the Two-Resonance Mode Method (Two-Resonance Mode 방법용으로 제작된 고온초전도 평행판 사파이어 공진기의 마이크로파 특성)

  • Jung, Ho-Sang;Yang, W.I.;Lee, J.H.;Lee, Sang-Young
    • Progress in Superconductivity
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    • v.11 no.2
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    • pp.106-111
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    • 2010
  • Sapphire resonators with $YBa_2Cu_3O_{7-\delta}$ (YBCO) endplates have provided a way to realize extremely high quality factor due to the extremely low dielectric loss of sapphire and conductive loss of YBCO films, which enables to measure the low surface resistance of superconductor films at microwave frequencies. We present microwave properties of HTS sapphire resonators designed for measuring the surface resistance of HTS films at millimeter-wave frequencies by using the two-resonance mode dielectric resonator method. Despite enhanced surface resistance ($R_S$) of YBCO films due to the quadratic frequency dependence of the $R_S$, the unloaded quality factor ($Q_0$) of the $TE_{021}$ mode sapphire resonator still appears to be well above $1\;{\times}\;10^6$ at a mm-wave frequency of 38 GHz at 10 K. However, it appears that the $TE_{012}$ mode $Q_0$ is unexpectedly low despite that the corresponding resonance peak looks uncoupled with parasitic modes. We discuss possible reasons for the unexpected results using the surface resistance at the $TE_{021}$, $TE_{012}$, and $TE_{011}$ mode frequencies.

Design of 3-D resonator for improvement of interference in ETCS (ETCS 신호 간섭 개선을 위한 3-D 공진기 설계)

  • Kim Ho-Yong;Lee Hong-Min
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.9 s.351
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    • pp.99-104
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    • 2006
  • In this paper, the conventional 2 dimensional metamaterial structure has degeneration of shielding characteristic in cross polarization effect. The proposed 3-D resonator is designed for reduction of cross polarization effect. The proposed 3-D resonator using LTCC consists of 2-D parallel resonators on X-axis, Y-axis and Z-axis. The 2-D parallel resonator consists of two plate and one via. When the co-polarization electric filed is excited, the resonance frequency of 3-D resonator is 5.024GHz. The stop bandwidth is 19MHz. When the cross-polarization electric field is excited, the resonance frequency of 3-D resonator is 4.825GHz. The stop bandwidth is 19MHz. The proposed 3-D resonator achieve reduction of cross-polarization effect. The concrete consists of proposed 3-D resonator and absorbtion materials. The concrete will be applied for reduction or interference signal of ETCS(Electric Toll collection system).

Suppression of Parasitic Resonance Modes for the Millimeter-Wave SiP Applications (밀리미터파 SiP 응용을 위한 기생 공진 모드 억제)

  • Lee Young-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.9 s.112
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    • pp.883-889
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    • 2006
  • In this paper, parasitic resonance modes generated in a conductor backed coplanar wave guide(CBCPW) and stripline band pass filter(BPF) and the oscillation phenomena of a 40 GHz power amplifier module(PAM) are analyzed and several methods to suppress them are presented for low-temperature co-fired ceramic(LTCC) based millimeter-wave RF System-in-Package(SiP) applications. Parasitic rectangular wave guide(RWG) modes of the CBCPW structure are completely suppressed in the operation frequency band by decreasing the distance between its vias and by increasing the mode frequency. In the stripline structure, RWG resonance modes are clearly eliminated by removing some vias facing each other and by placing them diagonally. In the case of the 40 GHz PAM, in order to reduce a cross talk due to radiation that is generated from interconnection discontinuities, high isolation structures such as embedded DC bas lines and CPW signal lines are used and then the oscillated PAM is improved.

Nacl Aqueous Solution Concentration Detection Using Slot-Coupled Capacitor Resonator (슬롯결합 커패시터 공진기를 이용한 Nacl 수용액 농도 검출)

  • Yun, Gi-Ho
    • Journal of the Korea Convergence Society
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    • v.9 no.11
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    • pp.29-35
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    • 2018
  • In this paper, we proposed a high sensitivity sensor that can detect the concentration change of Nacl aqueous solutions by using a slot coupling capacitor resonator in sub-microwave band. The resonator applied to the sensor consists of a parallel plate capacitor connected to an inductive slot utilizing the ground plane of the microstrip line. Based on the measurement data of the dielectric characteristics according to the concentration change, the resonance frequency was determined in the UHF band where the concentration change is evident and the Nacl aqueous solution is inserted into the capacitor. Based on the simulation, the proposed resonator was designed and fabricated. The concentration level was varied from 0 to 400 mg/dl as 100 mg/dl step, and the transmission scattering coefficient ($S_{21}$) was successfully measured. Experimental results show that it is applicable to the concentration detection sensor in Nacl aqueous solution by obtaining minimum 1.8 dB($S_{21}$) at each step.

Fluid Flow and Heat Transfer Characteristics around a Surface-Mounted Module Cooled by Forced Air Flow by Piezoelectric Cooling Fan (압전세라믹 냉각팬에 의한 강제 공랭 모듈 주위의 유체유동과 열전달 특성)

  • Park, G.J.;Park, S.H.
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.272-277
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    • 2003
  • This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. A flexible PZT fan with distortion in a fluid transport system of comparatively simple structure which was mounted on a PCB in a parallel-plate channel($450{\times}80{\times}700mm^3$) accelerates surrounding fluid locally. Input voltages of 20-100V and a resonance frequency of 23Hz were used to vibrate the cooling fan. Input power to the module was 4W. The cooling effect using a PZT fan was larger than that of free convection. Fluid flow around the module were visualized by using PIV system. The temperature distribution around heated module were visualized by using liquid crystal film(LCF). We found that the flow type was y-shaped and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.

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The Field of Power/Ground Planes influenced by the HPEM Source, and its Damage Reduction

  • Kahng, Sung-Tek;Kim, Hyeong-Seok
    • Journal of Electrical Engineering and Technology
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    • v.7 no.3
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    • pp.406-410
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    • 2012
  • This paper looks into the field inside the wide rectangular box structure that is excited by the High Power Electromagnetic(HPEM) source as a potential threat to electric grid and communication networks causing malfunction or destruction. The rectangular box is assumed power/ground planes and its internal field is calculated by the cavity model with the lightning strike excitation as an HPEM pulse. The accuracy of the calculation method employed here is validated through a $156mm{\times}106mm{\times}508{\mu}m$ parallel metallic plate case which is manufactured and tested, and is applied to the size of a building. With the help of the cavity model that takes into account loading, the level of the electric field is shown to decrease when a metal pillar is loaded between the power and ground planes.

Heat Transfer Characteristics Around a Surface-Mounted Module Cooled by Piezoelectric Fan (압전세라믹 냉각홴에 의한 강제 공랭 모듈 주위의 열전달특성)

  • Park, Sang-Hee;Park, Gyu-Jin;Choi, Seong-Dae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.7
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    • pp.780-788
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    • 2004
  • This paper reports the fluid flow and heat transfer around a module cooled by forced air flow generated by a piezoelectric(PZT) cooling fan. The fluids are locally accelerated by a flexible PZT fan which deflects inside a fluid transport system of comparatively simple structure mounted on a PCB in a parallel-plate channel(450${\times}$80${\times}$700㎣). Input voltages of 20-100V and a resonance frequency of 23㎐ were used to vibrate the cooling fan. Input power to the module was 4W. The fluid flow around the module was visualized by using PIV system. The temperature distributions around a heated module were visualized by using liquid crystal film(LCF). The cooling effect using a PZT fan was independent of the vent area ratios at the channel inlet and was similar to the forced convection cooling. We found that the flow type was Y-shape and the cooling effect was increased by the wake generated by a piezoelectric cooling fan.