• 한국항공우주학회지
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• 제38권1호
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• pp.80-86
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• 2010

본 논문은 현재 KAIST 인공위성연구센터(SaTReC)에서 개발하고 있는 과학기술위성3호 (STSAT-3) 위성본체의 S대역 통신채널 중 송신기 개발에 관하여 서술하고 있다. STSAT-3의 통신시스템은 위성제어 및 상태정보 전송을 위하여 S대역을 사용하며 임무수행용 통신채널로는 X대역을 사용하고 있다. S대역 송신기(S band Transmitter, STX)는 변조기, 주파수 합성기, 파워 앰프, 전력공급기 로 구성되어 있다. 변조 방법으로는 주파수 천이방식(Frequency Shift Keying, FSK)을 사용 하며 위성체와는 RS-422통신 방식을 이용한다. STSAT-3의 STX는 모듈화에 근거하여 설계 및 제작 되었으며 1.5W(31.7dBm) 송신 출력에 1E-5 비트오율(BER) 성능을 만족한다. 현재 성능시험, 환경시험(진동시험, 열진공시험)을 성공적으로 마쳤다.

• 대한전자공학회논문지SD
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• 제47권11호
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• pp.65-71
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• 2010

본 논문에서는 3.1~10.6 GHz 대역에서 14개 LO 신호를 발생하는 MB-OFDM UWB 시스템용 LO 생성 회로에 대한 새로운 구조를 제안한다. 제안하는 LO 생성 회로는 저전력 설계를 위해 하나의 PLL을 사용하면서 주파수 합성과정에서 반드시 필요로 하는 비선형 회로의 숫자를 최소화하고, 동시에 주파수 합성과정에서 발생되는 주요 spurious를 UWB 대역 밖에 존재시킴으로서 spurious 문제를 보다 근본적으로 해결하였다. 제안하는 LO 생성 회로는 $0.13-{\mu}m$ CMOS 공정으로 설계 되었으며, 1.5 V의 공급전압으로부터 93~103 mW의 전력을 소모한다. 모의실험 결과, 모든 14개의 LO 신호 스펙트럼에서 최소 41 dBc 이상의 in-band spurious suppression과 3 nsec 이하의 밴드간 스위칭 시간을 갖는다.

• 한국전자통신학회논문지
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• 제8권10호
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• pp.1427-1434
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• 2013

본 논문에서는 이동통신용 단말기 PCB Layout 위에 내장형 칩 안테나를 직접 설계하여 DCS(1.71~1.88GHz) 대역, PCS(1.75~1.87GHz) 대역 및 UPCS(1.85~1.99GHz)대역에서 공통으로 사용할 수 있는 이동통신용 트리플밴드 칩 안테나를 설계하였다. 안테나의 특성 해석을 위해서 Single, Dual, Triple Band 안테나를 설계 및 측정하였다. 설계된 안테나들은 제작하여 LTK(Laird Technologies Korea)에서 네트워크 분석기에 의해서 측정되었다. 트리플 광대역 특성은 1.71GHz~1.99GHz의 대역에서 동작하는 설계된 안테나의 측정된 대역폭(V.S.W.R<2.0)을 실현시켰다. 이 안테나의 크기는 $19mm{\times}4mm{\times}1.6mm$으로 설계하여 매우 소형화시켰으며, 칩 안테나의 단점인 좁은 대역폭을 크게 개선시켰다. 그리고 실험 측정 성능들은 시뮬레이션 성능들과 매우 유사함을 보여 주었다.

• ETRI Journal
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• 제31권3호
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• pp.247-253
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• 2009

We propose a Ku-band driver and high-power amplifier monolithic microwave integrated circuits (MMICs) employing a compensating gate bias circuit using a commercial 0.5 ${\mu}m$ GaAs pHEMT technology. The integrated gate bias circuit provides compensation for the threshold voltage and temperature variations as well as independence of the supply voltage variations. A fabricated two-stage Ku-band driver amplifier MMIC exhibits a typical output power of 30.5 dBm and power-added efficiency (PAE) of 37% over a 13.5 GHz to 15.0 GHz frequency band, while a fabricated three-stage Ku-band high-power amplifier MMIC exhibits a maximum saturated output power of 39.25 dBm (8.4 W) and PAE of 22.7% at 14.5 GHz.

• 한국위성정보통신학회논문지
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• 제3권2호
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• pp.7-12
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• 2008

The study discussed the link analysis for the Ka band satellite broadcasting service in Korea with respect to the transmission schemes based on the DVB-S2 standard. To analyze the effect of the rain fading to the link budget, we estimated the rain attenuation from the measured rainfall intensity in Korea. We analyzed the link budget for the Ka band transponders of Koreasat-3, and DirecTV BSS-99W, and showed the possible link availability with the DVB-S2 transmission schemes for each transponder. Based on the link analysis of the available satellites with the Ka band transponders, we suggested the required EIRP for the satellite which will be employed for the Ka band satellite broadcasting service in Korea.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.99-106
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• 2001

An overview of Silicon Carbide (SiC) Static Induction Transistor (SIT) development is presented. Basic conduction mechanisms are introduced and discussed, including ohmic, exponential, and space charge limited conduction (SCLC) mechanisms. Additionally, the impact of velocity saturation and temperature effects on SCLC are reviewed. The small-signal model, breakdown voltage, power density, and different gate structures are also discussed, before a final review of published SiC SIT results. Published S-band (3-4 GHz) results include 9.5 dB of gain and output power of 120 W, and L-band (1.3 GHz) results include 400 W output power, 7.7 dB of gain, and power density of 16.7 W/cm.

• 한국멀티미디어학회논문지
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• 제22권12호
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• pp.1430-1437
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• 2019

In this paper, we proposed a methodology for estimating rainfall intensity using a W-band FMCW automotive radar signal which is the core technology of autonomous driving car. By comparing and analyzing the results of rainfall and non-rainfall observation, we found that the reflection intensity of the automotive radar is changed with rainfall intensity. We could confirm the possibility of deriving the quantitative precipitation estimation using the methodology derived from this result. In addition it can be possible to develop a new paradigm of precipitation observation technique by observing various events together with the weather radar and the ground rainfall observation equipment.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.109-116
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• 2006

This paper presents a real time distance measuring device using a W-band linear frequency modulated continuous wave(FMCW) radar and TMS320C6701 digital signal processor(DSP). We used FFT operation for measuring distance with the beat signals and the results of FFT could be converted to distance with ease. We presented how to implement a real time miniaturized hardware system including network protocols using a single DSP core. Also how to control the modulation signal of FMCW system to compensate the VCO nonlinearity using the Time Gating control of DSP is presented. We have shown that the proposed system has good performances for measuring distance in real time via outdoor environment experiments.

• 한국군사과학기술학회지
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• 제9권2호
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• pp.103-110
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• 2006

We present a W-band radiometer to detect the metal targets on the ground environment. The type of the designed radiometer is the total power radiometer(TPR) for the simple configuration. The front end of the TPR consists of only the Mixer and LO for miniaturizing the system. Because the radiometer system does not use the low noise amplifier, we use matching circuits and a diode detector configured as a voltage doubler to compensate the degradation of sensitivity. We solve the temperature variation problems by filtering the reference voltages of the radiometer output signals. Through some experiments, we have verified that the designed radiometer system has good performances in detecting metal targets lying at several hundred meters.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권2호
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• pp.161-167
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• 2004

Silkworms sex determination drew high attention from researchers. Sex chromosomes on the silkworm are of ZW type for females and ZZ type for males. Chromosome W plays an important role in sex determination. Although several molecular linkage maps have been constructed for silkworm, very few markers are discovered on the W chromosome. In order to look for molecular markers and to further locate the Fern gene on chromosome W, we used genomic DNA from both female and male larvae of a silkworm strain named 937 as PCR templates for RAPD amplification with 200 arbitrary 10-mer primers. The amplification results showed three female-specific bands, namely ${OPG-07_496}, {OPC-15_1,660} and {OPE-18_1,279}$. Further verification, however, revealed no band from OPG-07 and OPC-15 in either sex in the strain 798, but OPE-18 provided female-specific band in the strains Suluan7 and C108, and absent in both males and strain 798. This indicates that the bands from ${OPG-07_496} and {OPC-15_1,660}$ are probably female-specific in strain 937, and the band from OPE-18 was probably amplified from a common segment shared by most strains. The genomic DNAs from OPG-07 and OPC-15 were cloned and sequenced. Sequence analysis showed that the DNAs from OPG-07 and OPC-15 have high identities with the retrotransposable elements, and DNA from OPC-15 contains a portion of sequence which probably encodes an eukaryotic translation initiation factor 4E binding protein (eIF4EBP).