• Title/Summary/Keyword: coupler loss

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On-line Strain Measurement of Rotating Blade Using Fiber Bragg Grating Sensors and Beam Coupler (광섬유 격자 센서와 빔 커플러를 사용한 회전중인 블레이드의 변형률 측정 방법)

  • Lee, In-Jae;Lee, Jong-Min;Lee, Sang-Bae;Hwang, Yo-Ha
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.11 s.116
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    • pp.1172-1178
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    • 2006
  • Measurement of blade strain with sensors directly installed on the blade has one critical issue, how to send the sensor signal to the ground. Strain-gauges have been dominantly used to directly measure stress of a blade and either a slip ring or a telemetry system has to be used to send measured signal to the ground. However, both systems have many inherent problems and sometimes very severe limitations to be practically used. In this paper, new on-line strain monitoring method using. FBG(Fiber Bragg Grating) sensors and a beam coupler is introduced. Measurement of rotor stress using FBG sensors is nothing new, but unlike other system which installs all necessary instruments on the rotor and use telemetry system to send data to the ground, this system makes use of light's unique characteristic - light travels through space. In this new approach, single optical fiber with many FBG sensors is installed on the blade and all other necessary instruments can be installed at ground thereby giving tremendous advantages over slip ring or telemetry system. A reference sensor is also introduced to compensate the beam coupler's transmission loss change due to rotation. The suggested system's good performance is demonstrated with experiments.

Development of Dual Band Directional Coupler Applying Multi-layer Structure (다층 구조를 적용한 Dual band 방향성 결합기 개발에 관한 연구)

  • Yoo Myong Jae;Yoo Joshua;Park Seong Dae;Lee Woo S.;Kang Nam K.
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.2 s.31
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    • pp.43-47
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    • 2004
  • A coupler or divider is a microwave passive component used for power coupling or dividing. Regarding the trend of current telecommunication systems monolithic integration of passive components is highly desirable. In this study by the LTCC(Low temperature co-fired ceramics) technology a 2012 size type dual band coupler with multi-layer structure was fabricated. To achieve the desired coupling values for both DCS and EGSM bands, broad side coupled patterns were used with multi-layer structure. Its characteristics such as coupling, insertion loss, isolation and directivity values were measured and compared with simulation results.

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Design and Fabrication of SMD Type Backward Wave 3dB Coupler for PCS Basestation (PCS 기지국용 표면실장형 후진파 3dB 커플러의 설계 및 제작)

  • 박인식;김종규;신동호
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.6
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    • pp.1-7
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    • 1998
  • In this paper, SMD type backward wave 3dB coupler for PCS basestation application was designed, fabricated and measured. We designed that it could be replaced for commercial basestation system and it was 0.56 $\times$ 0.35 inches size. The test results show that coupler is well operated within frequency range of 1.75 ~ 1.98GHz, which is defined on PCS system. The coupler reveals insertion loss 0.295dB, isolation -30.31dB, amplitude balance 0.05dB, phase balance 0.02$^{\circ}$, input and output impedance matching -30.38dB, -39.72dB, respectively.

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Online Strain Measurement at Multiple Points on a Rotating Blade with Fiber Bragg Grating Sensors and a Rotary Optical Coupler (광섬유 격자 센서와 회전 광학 커플러를 사용한 회전하는 블레이드 여러 지점에서의 온라인 변형률 측정)

  • Lee, Jong-Min;Hwang, Yo-Ha
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.1
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    • pp.77-82
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    • 2008
  • Strain-gauges have been dominantly used to measure strain at various points on a rotor, however, either a slip ring or telemetry has to be used to send sensor signals to data acquisition instruments at stationary side. Both slip ring and telemetry have numerous inherent problems which force severe limitations in real applications. This paper introduces a new rotor condition monitoring system using FBG(Fiber Bragg Grating) sensors and a rotary optical coupler. A single optical fiber with many FBG sensors is installed on the rotor and an optical dynamic interrogator is installed at stationary side. The sensor signal connection between rotating part and stationary part is made by the rotary optical coupling method which makes use of light's unique characteristic-light travels through space. Broad band light source from the interrogator travels to the optical fiber on the rotor and reflected FBG sensor signals travel back to the optical fiber on stationary side and are connected to the interrogator. Rotary optical coupler's insertion loss change due to rotation is compensated by using a reference sensor installed at the center of the rotor. The proposed system's performance has been successfully demonstrated by accurately measuring strains at 5 points on a blade rotating at high speed.

Novel Quadrature Branch-line Coupler Using CPW-to-Microstrip Transitions (마이크로스트립 전이를 이용하는 CPW Branch-line 커플러)

  • Lee, Jung-Ho;Lee, Hae-Yeong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.5
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    • pp.10-16
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    • 2000
  • This paper presents new double-sided 3-dB branch-line coupler using CPW-to-Microstrip via-hole transitions for the multi-layer applications. The characteristic impedance is obtained using the even-odd mode method, and the circuit performance Is accurately estimated by the Finite Difference Time Domain(FDTD) method. The fabricated double-sided 3-dB branch-line coupler has less than 0.3 dB power dividing imbalance and 1。 phase imbalance, greater than 30 dB isolation, and 25 dB return loss over a 20% bandwidth centered at 2 GHz. Calculated and fabricated results show that this coupler provides better performance as compared to the conventional microstrip branch-line couplers.

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A Study on the Design and Fabrication of the Planar Light Waveguide type $2\times32$ Optical Coupler (평면도파로형 $2\times32$ 광커플러의 설계와 제작에 관한 연구)

  • 신기수;최영복;류근호;문동찬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.12B
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    • pp.2335-2341
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    • 1999
  • The $2\times32$ coupler consists of Mach-Zehnder interferometer and Y branch coupler. For the designs of this coupler, three dimensional rectangular core waveguide decomposed to two-dimensional structure by the effective index method. To optimize the waveguide structure, the confinement factor was investigated with two-dimensional finite difference Beam Propagation Method. The $2\times32$ coupler fabricated by simulation with height between Mach-Zehnder arms, H=$43.6\mu\textrm{m}$(path difference $0.668\mu\textrm{m}$) was showed best characteristics. In the results of dry etching of core layer, the etching rate of core layer was above 2600${\AA}$/min, the etching ratio of SiO2 to Al mask was 30:1 and the uniformity of etching was $\pm$5%. The maximum insertion loss and the uniformity of $2\times32$ coupler were below 19.2dB, 2dB respectively.

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Design and Fabrication of 5-Bit Broadband MMIC Phase Shifter (5-Bit 광대역 MMIC 위상 변위기 설계 및 제작)

  • 정상화;백승원;이상원;정기웅;정명득;우병일;소준호;임중수;박동철
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.123-129
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    • 2002
  • 5-bit broadband MMIC phase shifter has been designed and fabricated. For the broadband performance, 11.25$^{\circ}$, 22.5$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$ bit have been designed with Lange coupler and 180$^{\circ}$ bit has been implemented by using shorted coupled line with Lange coupler and $\pi$-network of transmission line. Due to Lange coupler with large size, the Lange couplers have been folded far circuit size reduction. Low loss PIN diode has been utilized as a switch for each bit. Fabricated 5-bit broadband phase shifter shows the measured results that RMS phase error of 5 major phases is 3.5$^{\circ}$, maximum insertion loss is 12.5 dB, and maximum input and output return loss are 7 dB and 10 dB, respectively. The size of fabricated phase shifter is 6.5$\times$5.3 $ extrm{mm}^2$.

Implementation of condition monitoring system in underground utility tunnels using inductive coupler (유도성 커플러를 이용한 지하공동구의 상태감시시스템)

  • Ju, Woo-Jin;Kim, Hyun-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.8
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    • pp.1597-1603
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    • 2017
  • The incidence of fire in underground utility tunnel is lower than other fires, but the damage caused by fire can cause social loss due to social management paralysis as well as economic loss. Hereupon, this paper presents the results of an empirical test on the construction of the underground utility tunnel condition monitoring system using the leakage coaxial cable installed in the underground utility tunnel. For this reason, a verification test was conducted by connecting a inductive coupler 200 Mbps power line communication modem with insertion loss characteristics of $-6{\pm}2dB$ to the installed the leakage coaxial cable installed in the underground utility tunnel. As a result, We confirmed sending/receiving of IP cameras up to 500 m. Therefore, it is judged that it is possible to construct a condition monitoring system for underground utility tunnel by using the leakage coaxial cables installed in the underground utility tunnels without installing additional communication lines for data transmission.

Design and Implementation of Microstrip Quadrature Coupler and High Power Transmitting/Receiving Switch Using Dynamic Loading Technique for 1-Tesal MRI System (동적 부하 기술을 이용한 1-Tesla 자기공명 영상 시스템용 마이크로 스트립 quadrature coupler 및 고출력 송수신 스위치의 설계 및 제작)

  • 류웅환;이미영;이흥규;이황수;김정호
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.3
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    • pp.1-11
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    • 1999
  • It is now common practice to utilize the quadrature RF coils to improve the signal-to-noise ratio (SNR) in the Magnetic Resonance Imaging (MRI) System. In addition, to make such an available SNR improvement, it is mandatory to use a well-designed quadrature coupler, which facilitates a perfect 3-dB coupling and quadrature-phase shift. However, the four ports matching condition has to be well considered during the RF excitation and the signal detection period. This work investigates the effects of such a mismatching condition (especially, due to patient) from the analysis, simulation, and real implementation and firstly proposes dynamic loading technique for a quadrature coupler and transmitting/receiving switch module to minimize a patient mismatching and enhance a system reliability. Also, we designed and implemented the quadrature coupler and transmitting/receiving switch module using microstrip. As a result, the SNR of our MRI system using the microstrip quadrature coupler and transmitting/receiving switch module with dynamic load increases 3 dB compared with the old one using USA quadrature switch. Also, the power capability of quadrature coupler and transmitting/receiving switch module is 5-kw peak power. Considering power loss and reduction of size, we used a RT/duroid 6010 substrate with high permittivity and for simulation we use Compact Software.

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Characterization of the effect of joint clearance on the energy loss of flexible multibody systems with variable kinematic structure

  • Ebrahimi, Saeed;Salahshoor, Esmaeil;Moradi, Shapour
    • Structural Engineering and Mechanics
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    • v.63 no.5
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    • pp.691-702
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    • 2017
  • Clearances are essential for the assemblage of mechanisms to allow the relative motion between the joined bodies. This clearance exists due to machining tolerances, wear, material deformations, and imperfections, and it can worsen the mechanism performance when the precision and smoothly-working are intended. Energy is a subject which is less paid attention in the area of clearance. The effect of the clearance on the energy of a flexible slider-crank mechanism is investigated in this paper. A clearance exists in the joint between the slider and the coupler. The contact force model is based on the Lankarani and Nikravesh model and the friction force is calculated using the modified Coulomb's friction law. The hysteresis damping which has been included in the contact force model dissipates energy in clearance joints. The other source for the energy loss is the friction between the journal and the bearing. Initial configuration and crank angular velocity are changed to see their effects on the energy of the system. Energy diagrams are plotted for different coefficients of friction to see its influence. Finally, considering the coupler as a flexible body, the effect of flexibility on the energy of the system is investigated.