• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.107-112
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• 2004

We propose the optimum TO-can package design in SFF/SFP optical transceiver modules to improve 3dB-bandwidth. The frequency response of TO-38 package is measured and compared to simulation where the 3dB-bandwidth was 3.5GHz. For a higher operating bandwidth (>15GHz), the new optimized physical geometries of TO-can package such as bonding-wire, lead and material was suggested. The optimal result of simulation shows that TO-can package can be used at a higher bit rate optical module of 10Gbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.795-806
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• 1996

A structure which transmits and receives 3 subscribers packet data through an optical splitter node in an optical subscriber network of PON wave suggested and realized. All the functions which are necessary to use PON structure such as 155.52Mb/s multiplexer/demultiplexer of down-stream signal, 25.92Mb/s multiplexer/demultiplexer of up-stream signal, frame synchronizer, and phase aligner for aligning phase of the clock and received data have been integrated within 2 ICs using CMOS technonology. TDMAtechnology was suggested for up-stream transmission. In the optical up-stream transmission of the urst signals transmissionquality degradataion by APC and AGC of optical tranceiver was observed. By compensating the degradation, more than 17dB of link budget which is enough to satisfy 11.2dBthat is required in SWAN of PON architecture has been obtained with optical transceiver whose power and sensitivity are -17dBm and -34dBm respectively.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.42-45
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• 2001

최근 기능 및 기술인력의 부족과 인건비 상승에 따른 공사비 증가에 능동적인 대처, 건설공사의 품질향상, 공기단축 등을 위하여 각종 건설공사 부분에서 합리화, 기계화가 활발히 진행되고 있다. 그러나 이러한 것들을 적용하기 위하여 개발된 신기술 혹은 신공법에 대한 건설기술자의 미숙지, 부적절한 시공, 무리한 적용 등의 다양한 원인이 결부되어 콘크리트구조물에서 균열발생이 발생되는 경우가 종종 발생되고 있다.(중략)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.481-487
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• 2014

In this paper, we have proposed gigabit serial transceiver based on backplane architecture at the satellite communication digital transponder. The transponder supports the full combinational switching function with broadband multi-channel using programmable device - Xilinx space-grade Virtex-5 FPGA. In order to implement the switching function, GTX transceiver solution inside Virtex-5 FPGA is used. Also hardware implementation is simple because of no additional component. In order to use a GTX transceiver, signal integrity(SI) simulation of PCB design is essential. We investigate the characteristics of the S-parameter, eye diagram, channel jitter of GTX transmission line and conform that GTX Transceiver operates without error. Finally the proposed PCB design will be utilized at satellite communication digital transponder EQM-2(Engineering Qualification Model-2).

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.891-894
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• 2008

This study was performed to investigate how to design, where to construct, why to degrade, what plan to use systematically the underground structures such as underpass, underground passageways. About 50% of the underground structures are located on Seoul, Kyungi-Do. In design of the underground structures such as underpass, underground passageways, the required conditions are defined. And also in construction stage, the conditions of soil, required structure depth, site characteristics, reasonable construction method, are investigated. In the selection of details for underground structure, the items mainly considered, are the wall and column type, the sidewalk type, anchoring-system type, the water-proofing method, entranc shape. The reason and the adequate measures for the degradation of concrete structure are also investigated. The initial cracking properties due to the thermal characteristic are considered. The state of the art report on the new technologies are reviewed. The recent project for the systematically application to the underground structures is reviewed.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.491-500
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• 2012

In this paper, a new loopback BIST structure which is effective to test RF transceiver chip and LNA(Low Noise Amplifier) in the chip is presented. Because the presented BIST structure uses a baseband processor in the chip as a tester while the system is under testing mode, the developed test technique has an advantage of performing test application and test evaluation in effectiveness. The presented BIST structure can change high frequency test output signals to a low frequency signals which can make the CUT(circuits under test) tested easily. By using this technique, the necessity of RF test equipment can be mostly reduced. The test time and test cost of RF circuits can be cut down by using proposed BIST structure, and finally the total chip manufacturing costs can be reduced.

• 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 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1109-1114
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• 2003

In this paper, the electric characteristic of the SGPS with slot in the ground plane is similar to the parallel resonant circuit. When the slot length in SGPS is equal to the half wavelength of specific frequency, the characteristic of SGPS represent the large attenuation at the specific frequency. We found out the relation between attenuation and resistor on the slot in SGPS and we designed the variable attenuator for MMIC using the variable resistor. This attenuator can be applied to AGC circuit in transceiver if the PIN diode is used replace for resistor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1304-1310
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• 2010

This study is to design FMCW radar transceiver of K-band which is used to detect and track approaching high speed targets with low altitude. The transmitter needs high output power due to small RCS targets and wide beamwidth of transmit antenna. Multi-channel receivers are required to detect and track targets by interferometer method. Transmitter consists of high power amplifier, waveguide switch, and frequency up-converter. Receiver is composed of five channel receivers, up and down converters, X-band local oscillator and waveform generator. Before manufacturing it, the proposed architecture of transceiver is proved by modeling and simulation using several parameters. Then, it is manufactured by using industrial RF components. The performance parameters are measured through experiment. In the experiment, transmitting power and receiver gain were measured with 39.64 dBm and 29.1 dB, respectively. All other parameters in the specification were satisfied as well.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.172-182
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• 2014

In this paper, is is presented the result of design and fabrication for X band T/R module using in active array radar. The high power RF circuit was fabricated using GaN element, so that high power and high efficiency was fulfilled comparing with the previous T/R module that have under 50 W output power for X band. Designed X band T/R module demonstrated 200 W(53 dBm) peak power, 20 us pulse width with 0.4 dB pulse droop and 20 % duty cycle. And it has characteristics of 26 dB receive gain and 4.5 dB noise figure. The structure was applied to prevent serious damage of receive path and GaN HPA by transmitting power during trasmit time of a pulse radar.