• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1103-1104
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• 2011

This paper presents 1kW BLDC motor drive system and magnetic coupler for water thrust in ROV. In order to get a high performance and reliability, some design flow is proposed in this paper. The proposed system is verified by the experimental tests.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.21-26
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• 2002

In the conventional star coupler, a certain amount of loss should be expected because lateral diffraction is used for the power distribution. In this paper, we propose a new design of a low loss star coupler which employs UV-written tapered waveguides and an AWG based on the low loss star couplers, and investigate their various characteristics. The loss of the UV-written star coupler is lower than that of the conventional star coupler, and the AWG device based on the UV-written star couplers shows low loss characteristics.

• Archives of Reconstructive Microsurgery
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• v.24 no.1
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• pp.20-23
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• 2015

Despite increased utilization of microvascular anastomotic coupler (MAC) devices, the consequences have yet to be fully explored in terms of vascular regeneration. Removal of an exposed venous coupler is described herein, documenting normal circulatory flow through the remodeled site of application. A 25-year-old man who underwent open reduction and rigid fixation elsewhere for traumatic calcaneal fracture ultimately presented with a necrotic postoperative wound. The debrided defect was treated by free thigh perforator flap, incorporating a MAC device. Three months later, the flap remained viable, but the MAC itself was exposed. Structural integrity of the vessel and blood flow were sustained as the device was carefully removed, confirming true vascular remodeling in this example of MAC usage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.317-320
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• 2003

Nowadays, the study on the ceramic components and modules used in telecommunication system is being performed. Coupler is a microwave passive component used for power coupling or dividing and directional coupler is designed to be possible optional dividing percentage. In our research, We developed 14dB and 19dB directional couplers of DCS band. The good characteristics, the target insertion loss and high isolation, of couplers is obtained by LTCC processing using a ceramic material.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1440-1442
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• 2007

A high-voltage motor has had many problems due to its frequent startup, standstills and occasions of long period operation. As for a solution to the problem, many advanced countries have developed an on-line insulation diagnosis sensor and a same type of system and put them in use. Recently, even in the domestic market, a ceramic coupler has been developed and attempted to be applied in the field. This paper proposes an on-line insulation diagnosis system when operating a high-voltage motor along with the use of a domestic ceramic coupler. The proposed system is composed with a ceramic sensor, a PDMS-HM, and a Remote Monitoring System. As the result of comparing this system with a PDAS, which is an expensive full A/D method, the reliability of the system has been verified, and furthermore, it is in the process of being commercialized.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.200-205
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• 2014

In this paper, 5.8GHz band $4{\times}4$ Butler matrix is designed using easily accessible commercial $90^{\circ}$ hybrid coupler and semirigid coaxial cable as a transmission line. This Butler matrix is very flexible to changes of antenna system specification like a frequency band because $90^{\circ}$ hybrid coupler changing is all to do. The result of design is the distance of $2{\times}2$ array antenna element is $\sqrt{2}{\lambda}/4$, the 4 beam directions are diagonal of array antenna and phase shifter is not necessary. The beam width is roughly $25^{\circ}$ narrower because of array antenna geometry and the side lobe is about 10dB higher partially than theoretical beam pattern. But the overall beam pattern is similar with theoretical beam. This Butler matrix can be applied to switching beam antenna of 5.8GHz band Wi-Fi and WAVE system.

• 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.

• 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.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.25-32
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• 2017

In this paper, a fabrication method of low-loss tapered optical fibers coupler using hydrofluoric acid with surface tension driven is proposed. The proposed fabrication method is very simple compared to flame-based method, and shows low excess insertion losses compared to polishing method. The adiabatic-tapered structure along the coupling region of the coupler shows wavelength independent characteristic over the C-band in optical communication system, and will enable promising applications.