• Title, Summary, Keyword: Cavity resonator

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Design of the Rain Sensor using a Coaxial Cavity Resonator (동축 공동 공진기를 이용한 물방울 감지 센서 설계에 관한 연구)

  • Lee, Yun-Min;Kim, Jin-Kook
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.18 no.5
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    • pp.223-228
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    • 2018
  • In this paper the water sensor using a coaxial cavity resonator is designed and manufactured. The water sensor which can sense water drop linearly has been constructed with voltage controlled oscillator(VCO), coaxial cavity resonator, RF switch, RF detector, A/D converter, DAC and micro controller. The operating frequency range of the designed water sensor is from 2.5GHz to 3.2GHz and the input voltage and current source are 24[V/DC] and 1[A]. The designed sensor circuit includes VCO, RF switch, RF detector which varies the frequency characteristics of the devices in the high frequency of 3GHz. And so we should correct the error of the frequency characteristics of those devices in the sensor circuit. To do this, we make the reference path which switches the signals to the RF detector directly without sending it to the resonator. According to the result of simulation and measurement, we can see that there is 0-50MHz difference between simulated resonator frequency and manufactured resonator frequency.

Development of TEM Coil for Animal Experiments at 3T MRI System

  • Chu, Myung-Ja;Choe, Bo-Young;Kim, Kyung-Nam;Chung, Sung-Taek;Oh, Chang-Hyun;Lee, Hyoung-Koo;Suh, Tae-Suk
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.365-366
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    • 2002
  • A novel TEM resonator coil was developed for the imaging of small animals. The functional elements of the TEM resonator were 8 inner conductors, distributed in a cylindrical pattern and connected at the ends with capacitors to the cylindrical outer shield. The TEM resonator coil with cavity elements was robust to the surrounding influences due to the self-shielding structure. The TEM resonator coil with high Q factor could provide high quality MR images at 3.0T MRI system. Also, the TEM resonator coil has an advantage for a fine tune with length adjustment of each cavity elements. Thus, The TEM resonator coil at 3.0T, even higher field could be used in the research studies.

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Design of Contactless Power Transmission Device Using Cavity Resonator (공동공진기를 이용한 무접점 전력 전송 장치 설계)

  • Chang, Tae-Soon;Kim, Yong-Nam;Hur, Jung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.11
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    • pp.1025-1033
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    • 2011
  • In this paper, we introduce the contactless power transmission device for transmitting the power with the resonant characteristic of the cavity resonator. When transmitting the power, the contactless power transmission device begins to work in the condition where the transceiver adheres closely. The transceiver is electrically separated because there is no conductive terminal outside and the size of the receiver required for the electric power transmission can be minimized. The cavity resonator comprises slots for the input port and output port in the upper side conductor plate of the cavity and forms the input port and output port using the stripline structure at this upper part. The some of output port is separated from it and the electric power receiver is formed thus the union can be possible. The rest except electric power receiver become the electric power transmitter, which includes the input port of stripline-slot coupling, cavity, and the slot of the output port. If the transmitter and the receiver are combined, they become the form in which the electricity is transferred from the input port to the output port in a cavity resonator. The center frequency of the contactless power transmitter manufactured is 5.782 GHz. and $S_{21}$ is measured as -1.07 dB. It is confirmed that the high electric power transfer rate is approximately 78 %.

Design of An Open-Ended Coaxial Cavity Resonator (한쪽 면이 열린 동축 공동 공진기의 설계에 대한 연구)

  • Lee, Yun-Min;Kim, Jin-Kook;Hur, Jung
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.13 no.4
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    • pp.201-208
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    • 2013
  • This paper is a study of an empirical design of an open-ended coaxial cavity resonator. It can be done by using the radius of the inner conductor, the inner radius and the length of the resonator. However, the basic coaxial transmission -line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2 mm, 5 mm, 10 mm respectively for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, 6.5 GHz respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open-ended coaxial cavity resonator by applying the basic coaxial transmission-line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator.

Spray Characteristics of Internal-Mixing Twin-Fluid Atomizer using Sonic Energy (음향에너지를 이용한 내부 혼합형 이유체 분사노즐의 분무특성)

  • Cho, H.K.;Kang, W.S.;Seok, J.K.;Lee, G.S.;Lee, C.W.
    • Journal of ILASS-Korea
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    • v.4 no.3
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    • pp.32-41
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    • 1999
  • In this research, internal-mixing twin-fluid atomizer using sonic energy is designed and manufactured. We are trying to intimate high efficiency twin-fluid atomizer to obtain good liquid atomization in the low pressure region. Define of geometric form of atomizer, characteristics of spray is influenced by position, depth and height variation of cavity resonator, variation of sound intensity and resonant sound frequency with liquid flow rate. The liquid atomization is promoted by multi-stage disintegration of mixing flow of gas with liquid and the optimum condition of position and depth of cavity resonator according to sonic energy is obtained from the condition at a=2.5mm and L=2mm. The velocity distribution of droplets shows negative value due to recirculation region at the center of axial, and as the radial direction distance is far, the velocity distribution of droplets decrease slowly after having a maximum value. However velocity and SMD show nearly uniform distribution at the down stream and as result compared to Nukiyama and Tanasawa's equation. atomization of mixing flow with air and liquid dispersing from the outlet of the nozzle is promoted by the effect of collision at the cavity resonator.

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Topology Optimization of Muffler Hole using Genetic Algorithm (유전자 알고리즘을 이용한 머플러 구멍 위상최적설계)

  • Wang, Semyung;Dikec, Altay;Hwang, Insoo;Kwon, Byoungha
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1205-1205
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    • 2003
  • Rotary compressors are one of the most important parts of air-conditioners in the industry This device usually has noise problems during the circulation process of the refrigerant and muffler is used for the noise reduction. The acoustic performance of the muffler depends on its shape and its hole locations on the upper surface. Therefore finding the optimum location of the muffler holes is a topic of increasing importance in the compressor industry. In this research the optimization of the muffler hole locations and the importance of the resonator cavity on the lower surface of the muffler in acoustic point of view is studied. At first, the topology optimization for the 2 hole muffler is performed based on a model without resonator cavity by using genetic algorithm. The 2 hole muffler's acoustic analysis and experiment results are matching, however, the optimized model's results are not. By adding the resonator cavity and also by changing the cavity shape, the acoustic analysis and experiment result comparison is Performed for different cavity shapes. The topology optimization of the revised model with cavity is carried out for noise reduction. Finally, the optimized design is produced and tested for validation.

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A Study on the Acoustic Absorption Character of a Helmholtz Resonator in Model Chamber (모형연소실에 장착한 헬름홀츠 공명기의 흡음특성에 관한 연구)

  • Park, Ju-Hyun;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.399-402
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    • 2009
  • Acoustic design parameters of a Helmholtz resonator are studied experimentally and numerically for acoustic stability in a model acoustic tube. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. Helmholtz resonator on spring-damper system use were understanding for acoustic damping. The length of orifice and the volume of cavity of resonator are selected as design parameters for tuning of the resonator. Acoustic- damping capacity of the resonator increases with its cavity volume. And orifice length as increases with acoustic damping capacity was decreased.

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The effect of internal sound field and resonator on radiating sound of King Song-Dok bell : proposing effective size of resonator (선덕 대왕 신종 내부 음장 및 울림통이 신종의 소리에 미치는 영향과 새로운 울림통 크기의 제안)

  • Kim, Yang-Han;Park, Soon-Hong;Kim, Sea-Moon
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.5
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    • pp.60-67
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    • 1997
  • the famous King Song-dok Bell which was cast in A.D. 771, during Silla dynasty has significant xize of concave cavity which acts as Helmholtz resonator on the ground. To see the effect of this cavity and the bell's internal acoustic cavity on radiating sound of bell, three dimensional measurement of internal sound field was performed. In this paper, the dtail measurement procedure and results are carefully addressed. The effect of the cavity on the radiating sound of bell is investigated using simple and physically representative model. A new size of cavity is proposed.

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2-state 5-pole bandpass filter consisted of dual and tripe-mode cavity resonator (이중 및 삼중모드 공동 공진기로 구성된 2단 5-Pole 대역통과 필터)

  • 김상철;홍의석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.6
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    • pp.1251-1258
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    • 1997
  • Generally, it is very important to study selective coupling between cavities of the filter structure using multimode cavity resonator. In this paper, we have manufactured 5-pole bandpass filter(BPF) using dual and triple-mode cavity resonator. To do so, we have derived the formulas for coupling coefficient about coupling between TE-modes from TM/TE-mode's tangential and lognitudinal field intensities each other. To implement the Chebyshev response, the intercabity slot combining dual-mode and triple-mode is designed to couple one H-field of TE-mode parallel to slot plate. In this paper, specially it is derived the formulas for T $E_{11p}$-mode from TE-modes, and determined after obtaining location and size of intercabity slot from the equation. In this ppaer, based on this result, we designed and implmented teh bandpass filter operated at the center frequency of 14.5GHz with a Chebyshev response. For the manufactured cavity filter, dual-mode and triple-mode cavity are resonted by two orthogonal T $E_{113}$-modes, and by two orthogonal T $E_{113}$-modes and one T $M_{012}$-mode, respecitively. The 2-stage 5-pole BPF proposed in this paper has the insertion loss of -2.32dB, the reflection loss of -15dB in the passband, and the out-or-rejection of -67dB.

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A Measurement of Electromagnetic Property of Illite found in Young-dong Area (영동산 일라이트의 전자기적 특성 측정)

  • Kim, Jin-Chul;Lee, Won-Hui;Koo,K.W.;Hur, Jung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.267-270
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    • 2000
  • This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of illite used to cylindrical cavity resonators with moveable cap. A concentric dielectric-rod inserted cylindrical cavity resonator and an exact field representation of travelling wave mode are introduced for measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with concentric dielectric rod is analysed. A relative permittivity of dielectric in cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of travelling mode is exact. As a result, relative permittivity of dielectric materials were 7.820 at sample-1 and 7.894 at sample-2.

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