• 한국전자파학회논문지
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• 제27권5호
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• pp.471-481
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• 2016

밀리미터파 대역에서 동작하는 안테나의 성능 측정을 위한 컴팩트 레인지 설계 및 실험 결과에 대해 소개한다. 전기적 거대 구조인 컴팩트 레인지의 포물면 반사판에 의해 형성되는 측정영역의 평면파를 해석하기 위하여 물리광학 기법을 적용하였다. 제작한 밀리미터파 컴팩트 레인지는 측정영역 전계 분포 실험과 고이득 안테나 측정을 통해 성능을 검증하였다. 동작 주파수 75~110 GHz에서 측정영역 직경 50 cm를 갖도록 설계한 컴팩트 레인지의 전력 균일성은 0.75 dB 이하로 측정되었다.

• 대한전자공학회논문지SD
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• 제39권1호
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• pp.25-30
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• 2002

본 논문에서는 PECVD 장비를 이용하여 PHEMT 소자의 passivation 막으로 사용되는 Si₃N₄박막의 특성을 최적화하고, 0.25 ㎛급 PHEMT 제작에 적용하였다. 제작된 PHEMT(60 ㎛×2 fingers)의 소자 특성을 측정한 결과, passivation 후 드레인 포화전류와 최대 전달 컨덕턴스는 passivation 전보다 각각 2.7% 와 3%씩 증가하였으며, 전류이득 차단 주파수는 53 ㎓, 최대 공진 주파수는 105 ㎓ 였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.53-56
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• 2001

This paper has been developed a millimeter-wave radar to prevent car collision. This system needs to progress the problem as follows; (1) Increase of traffic accidents causing damage and injuries due to the increased number of motor vehicles and long distance driving, (2) Need for a device to help drivers who are in trouble due to bad weather conditions. (3) Need for a millimeter-wave radar as obstacles which need to be detected are small. This system is composited with some major technologies, Narrow beams to recognize obstacles or other objects, One-side circuit technology to prevent interference between electric waves, and Parts designed for radar products which are able to transmit millimeter - waves. The system has a various a application Field, Car distance auto-control system, prevent bump collision due to unexpected stoppage of the front car or careless driving, obstacle warning system, Car following system, and industrial and military purposes system. We have a looking forward to propose to develop field tests under various road conditions and hybrid car sensor by combining with other sensors

• Journal of Communications and Networks
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• 제16권5호
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• pp.512-522
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• 2014

This paper proposes fast millimeter-wave (mm-wave) beam training protocols with receive beamforming. Both IEEE standards and the academic literature have generally considered beam training protocols involving exhaustive search over all possible beam directions for both the beamforming initiator and responder. However, this operation requires a long time (and thus overhead) when the beamwidth is quite narrow such as for mm-wave beams ($1^{\circ}$ in the worst case). To alleviate this problem, we propose two types of adaptive beam training protocols for fixed and adaptive modulation, respectively, which take into account the unique propagation characteristics of millimeter waves. For fixed modulation, the proposed protocol allows for interactive beam training, stopping the search when a local maximum of the power angular spectrum is found that is sufficient to support the chosen modulation/coding scheme. We furthermore suggest approaches to prioritize certain directions determined from the propagation geometry, long-term statistics, etc. For adaptive modulation, the proposed protocol uses iterative multi-level beam training concepts for fast link configuration that provide an exhaustive search with significantly lower complexity. Our simulation results verify that the proposed protocol performs better than traditional exhaustive search in terms of the link configuration speed for mobile wireless service applications.

• Journal of electromagnetic engineering and science
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• 제10권4호
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• pp.316-321
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• 2010

This paper presents a novel fourth harmonic mixer with new structure. The traditional 3-ports fourth harmonic mixer and the novel fourth harmonic mixer are designed by ADS, HFSS and CST simulator. The mixers have been fabricated and tested. The size of the traditional 3-ports fourth harmonic mixer is $12{\times}15$ mm, and the best conversion loss is 18.7 dB according to the measurement. Since the traditional 3-port mixer size is too large to be ranked, we design a novel fourth harmonic mixer for imaging system. The width of the mixing module in the novel fourth harmonic mixer is only 3.65 mm, and this size is fully capable to meet the mixer unit space which is not greater than 5 mm. The simulation result shows that the mixer has good performance, and the experiment result shows that the best conversion loss of the novel fourth harmonic mixer is 16.3 dB at RF signal of 91.3 GHz.

• 대한의생명과학회지
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• 제17권1호
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• pp.79-84
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• 2011

Photodynamic therapy consists of a photosensitizer, suitable light source and oxygen. The excitation of the photosensitizer at a cancer mass results in oxidation which would ultimately reduce the mass via apoptosis. Millimeter wave (MMW) therapy has also been known to be effective on cancer cell mass reduction, human cell regeneration and immunity enhancement among the Russian clinicians and scientists. In the present study, the two modalities were combined to achieve synergistic effects while reducing the administration dosage of the photosensitizer, photogem, thus minimizing the side effects. The CT-26 adenocarcinoma cell mass was implanted on mice and the tumors were exposed to a simple MMW irradiation or a combined treatment of MMW and PDT. The treatments continued for 4 weeks and the size of the tumor was measured continuously. The significant therapeutic result of MMW was not found during 4 weeks, preferably more cancer recurrence possibility after MMW irradiation was observed. The results of this study suggest that the combination of MMW irradiation and photodynamic treatment should not be recommended. The result of the MMW treatment alone, however, displayed suppressive effect on cancer cell proliferation for both in vitro and in vivo. The results of the present study suggest that the millimeter wave therapy deserves a further study.

• 대한전자공학회논문지SD
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• 제44권7호통권361호
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• pp.1-8
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• 2007

고주파에서 동작하는 높은 출력전력과 dc-rf 변환효율을 가진 GaAs Gunn 다이오드에 대한 기본 연구로써, graded gap injector를 가진 planar 형태의 GaAs Gunn 다이오드를 제작하고 그 DC 특성을 살펴보았다. 제안된 에피 구조를 사용하여 GaAs Gunn 다이오드 소자를 설계, 제작하였으며 이동전자소자인 Gunn 다이오드의 DC 특성이 부성미분저항을 가짐을 확인하였다. 제작된 소자의 부성미분저항 특성을 다이오드의 cathode 반지름의 함수로 고찰하였으며, 이 과정을 통하여 계곡 간 전자이동 특성을 분석하였다.

• 한국통신학회논문지
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• 제36권10A호
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• pp.847-851
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• 2011

본 논문에서는 밀리미터파 응용에서 사용 가능한 우수한 성능의 MMIC (Millimeter-wave Monolithic Integrated Circuit) star 혼합기를 구현하였다. MMIC star 혼합기를 구현하기 위하여 PHEMT (pseudomorphic high electron mobility transistor) 공정 기반의 소오스와 드레인 단자를 연결한 쇼트키 (Schottky) 다이오드를 사용하였다. 혼합기의 측정 결과 LO 주파수가 75 GHz이며 전력이 10 dBm 인 경우, 81 GHz에서 86 GHz의 RF 주파수 범위에서 평균 13 dB의 변환손실 특성을 얻었다. RF-LO 격리도 특성은 30 dB 이상의 결과를 얻었으며 약 4 dBm의 P1 dB 특성을 얻었다. 전체 칩의 크기는 0.8 mm ${\times}$ 0.8 mm이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.593-597
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• 2002

The paper introduces a research on the W-band Millimeter Wave Radiometer(RADW92) through an airborne experiment. Microwave remote sensing images of part of the Yellow River and the WeiHe River are of fared. Analysis of factors influencing the image qualities as well as the resolutions to them are also included. The RADW92 is the first generation of Millimeter Wave Radiometer in China, which works with operating frequency 92 GHz, the bandwidth 2 GHz, the integration time 60ms, the system sensitivity 0.6k and the linearity better than 0.999. Cassegrain Antenna is designed for imaging by conically scanning. The result of the experiment suggested that RADW92 had been adequate for space use.

• 한국인터넷방송통신학회논문지
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• 제19권3호
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• pp.157-163
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• 2019

대함용 소형 밀리미터파 추적 레이다는 저속으로 기동 중인 큰 RCS를 갖는 바다위의 함정 표적에 대하여 TWS(Track While Scan) 방식을 통하여 실시간으로 표적을 탐색, 탐지 하여 추적하는 펄스 방식의 레이더이다. 본 논문에서는 소형 밀리미터파 추적 레이다의 성능을 실험실 무반향 챔버 환경에서 확인하기 위한 모의신호 발생장치 개발에 대하여 서술한다. 추적 레이다용 모의신호를 생성하기 위한 요구사항과 요구사항을 충족하기 위한 모의신호 발생장치의 하드웨어 구성과 추적 레이다와 연동하여 시험을 하고 성능을 분석하기 위한 GUI 프로그램을 기술하고 성능시험을 통해 구현한 모의신호 발생장치를 검증하였다.