• 한국컴퓨터정보학회논문지
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• 제5권4호
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• pp.55-61
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• 2000

ITU-R의 강우에 의한 교차편과 모델은 35 GHz까지만 적용가능하다. 본 논문에서는 빗방울의 형태에 따른 강우업자의 산란특성을 해석하고 실제의 강우환경에서 충분한 정확도를 가지는 교차편파에 대한 단순한 이론모델을 제안하였다. 이를 측정치 및 ITU-R 모델과 비교함으로써 밀리미터파대역까지 적용할 수 있는 교차편과 추정모델을 도출하였다.

• 천문학회보
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• 제38권1호
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• pp.27-27
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• 2013

Development of bolometer array and camera at millimeter and submillimeter wavelengths plays an important role for detecting submillimeter galaxies (SMGs) which appear to be very bright at the submillimeter and millimeter wavelengths. These SMGs, luminous infrared galaxies detected at mm/submm wavelengths seem to be progenitors of present-day massive galaxies and account for their considerable contributions to the light from the early universe and their expected high star formation rates (SFRs) if there is a close link between the SMG phenomena and the star formation activities and the interstellar dust in galaxies is mainly heated by the star light. In this talk, we review assembly of SMGs compiled with observations using the bolometer arrays and cameras and investigate their spectral energy distribution fits including the data at other wavelengths which trace the photometric properties and the red-shift distribution of galaxies. We find that these bright SMGs significantly contribute to the cosmic star formation rate density at red-shifts of 2-3 (about 8 %) for the spatial distribution of these galaxies.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.18-23
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• 2001

A fast-sweep broadband FM reflectometer system has been successfully developed and operacted at the DIII-D tokamak, producing reliable density Profiles with excellent spatial (1 $\leq$ cm) and temporal resolution (~100 $\mu$ s). The system uses a solid-state microwave oscillator and an active quadrupler, covering full Q-band frequencies (33~50 GHz) and providing relatively high output power (20~60 mW). The system hardware allows fu11band frequency sweep in 10 $\mu$ s, but due to digitization rate limit on DIII-D, sweep time was limited to 75~100 $\mu$ s. Fast frequency sweep has helped to reduce density fluctuation effects on the reflectometer phase measurements, thus improving reliability for individual sweeps. The fast-sweep system with high spatial and temporal resolution has allowed to measure fast-changing edge density profiles during plasma ELMS and L-H transitions, thus enabling fast-time sca1e physics studies.

• Journal of electromagnetic engineering and science
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• 제10권4호
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• pp.231-236
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• 2010

This study proposes a temperature compensation method of the complex permittivities of biological tissues and organs. The method is based on the temperature dependence of the Debye model of water, which has been thoroughly investigated. This method was applied to measured data at room temperature for whole blood, kidney cortex, bile, liver, and heart muscle. It is shown that our method can compensate for the Cole-Cole model using measured data at 20 $^{\circ}C$, given the Cole-Cole model based on measured data at 35 $^{\circ}C$, with a root-mean-squared deviation of 3~11 % and 2~6 % for the real and imaginary parts of the complex permittivities, respectively, among the measured tissues.

• ETRI Journal
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• 제40권1호
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• pp.89-100
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• 2018

Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use-case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof-of-concept wireless backhaul solution developed within the EU-KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over-the-air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

• 한국기계가공학회지
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• 제7권1호
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• pp.32-37
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• 2008

This paper presents a new precision stage by using the PZT actuator and stepping motor. The stage have the precision positioning mechanism that has been developed for generation displacements with nanometer accuracy and a millimeter dynamic range simulatneously. The stage is composed not of the mechanical elastic hinge but of the clamp, and only one PZT actuator. The displacement of stage is acquired by the control of the two clamp between the PZT actuator. The results of the FEM analysis in the contact part of the clamp and basic properties of the positioning system are also presented. Using the new stage proposed in this paper.

• ETRI Journal
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• 제26권1호
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• pp.61-64
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• 2004

We have explored the fabrication of an InP/InGaAs single heterojunction bipolar transistor (HBT) and a wave guide p-i-n photodiode (PD) on two kinds of double stacked layers for the implementation of an optoelectronic millimeter-wave monolithic integrated circuit (OEMMIC). We applied a photosensitive polyimide for passivation and integration to overcome the large difference between the HBT and PD layers of around $3{\mu}m$. Our experiment showed that the RF characteristics of the HBT were dependent on the location of the PD layer, while the dc performances of the HBTs and PDs were independent of the type of stacked layer used. The $F_t$ and $F_{max}$ of the HBTs on the HBT/PD stacked layer were 10% lower than those of the HBTs on the PD/HBT stacked layer.

• ETRI Journal
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• 제38권1호
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• pp.81-89
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• 2016

In this paper, a beam ID preamble (BIDP) technique, where a beam ID is transmitted in the physical layer, is proposed for efficient beam training in millimeter-wave cellular communication systems. To facilitate beam ID detection in a multicell environment with multiple beams, a BIDP is designed such that a beam ID is mapped onto a Zadoff-Chu sequence in association with its cell ID. By analyzing the correlation property of the BIDP, it is shown that multiple beams can be transmitted simultaneously with the proposed technique with minimal interbeam interference in a multicell environment, where beams have different time delays due to propagation delay or multipath channel delay. Through simulation with a spatial channel model, it is shown that the best beam pairs can be found with a significantly reduced processing time of beam training in the proposed technique.

• 전기전자학회논문지
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• 제16권2호
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• pp.116-120
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• 2012

본 논문에서는 밀리미터파 응용에 사용 가능한 우수한 성능의 50 nm InGaAs/InAlAs/GaAs metamorphic HEMT를 구현하였다. 게이트 길이가 50 nm이며 단위 게이트 폭이 30 ${\mu}m$인 2개의 게이트를 가지고 있는 MHEMT의 측정결과, 740 mA/mm의 드레인 포화 전류밀도와 1.02 S/mm의 상호전달 전도도를 얻었으며 전류이득차단주파수와 최대공진주파수는 각각 430 GHz와 406 GHz의 특성을 나타내었다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 추계기술심포지움논문집
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• pp.87-90
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• 2002

무선 통신 시스템의 광대역화에 따라 수십GHz 이상에서의 시스템 구성이 필요하다. 이러한 시스템의 상용화를 위해서는 수십GHz 이상에서의 고주파 특성 만족과 저비용의 공정이 요구된다. 본 연구에서는 후막 리소그라피 공정을 이용하여 미세라인 특성에 민감한 BPF를 설계.제작하였다.