• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.288-290
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• 1997

Pulsed laser ablation has been used to fabricate superconducting $YBa_2Cu_3O_{7-x}$(YBCO) thin films on MgO substrates. The epitaxial YBCO thin films were grown at $750^{\circ}C$ and oxygen partial pressure of 200 mTorr. The electrical property and the characteristics of the YBCO thin films have been studied by R-T measurement. scanning electron microscopy (SEM) and X-ray diffraction (XRD). A microstrip line resonator has been fabricated using YBCO superconducting thin films by photolithography and wet-etch process. The resonator has linear microstrip line separated by a gap of 0.278 mm. We observed a fundamental resonance peak at the frequency of 10.007 GHz.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.197-200
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• 2001

최근의 확산대역 통신 방식에 사용되는 주파수 합성기는 주파수 스위칭 시간이 중요한 요소가 되고 있다. FH-SS(Frequency Hopping Spread Spectrum) 송수신기에서 고속 주파수 합성기 설계는 채널 효율을 높이기 위해 매우 중요하다. 본 논문에서는 기존 PLL방식에 직접 접근 주파수 합성 (DDS) 방식을 응용하여 1 $\mu\textrm{s}$ 이하의 스위칭 시간을 갖는 고속 주파수 합성기를 설계하고, 이를 2.4GHz 대리의FH-SS 송수신기에 적용하여 시뮬레이션 결과 20% 이상의 채널 효율 개선 효과를 얻었다.

• 정보와 통신
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• 제16권10호
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• pp.64-74
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• 1999

무선 채널에서 제한된 주파수 대역폭을 최대로 활용하여 비디오 데이터를 전송하기 위해서는 고효율의 변복조 기법, 페이딩 보상 기업 및 효율적인 오류 정정 기법이 요구된다. 본 고에서는 RF 주파수가 2GHz 대역이고 주파수 대역폭이 200 KHz를 갖는 TDMA 방식에 의한 WLL 모뎀(이하 AdWiLL$^{TM}$이라 한다) 설계에 대하여 기술한다. AdWiLL$^{TM}$모뎀의 핵심 기술로는 채널 특성을 실시간으로 분석하여 최적의 송수신 조건을 결정하는 channel probing 기술, 페이딩 환경에서 다중 레벨 QAM변복조를 가능하게 하는 적응출력제어 기술, WLL전파 환경과 서비스가 고려된 연접 부호(concatenated coding)를 통한 순방향 오류 정정(FEC) 기술, 송수신 성능 향상을 위한 범포밍 기술이 포함된다. 구현된 모뎀으 고정 무선 채널 환경에서 16 채널에서 32Kbps ADPCM 음성 신호를 동시에 송신할 수 있으며, 협대역 ISDN에서 제공하는 전송속도로 비디오 데이터의 전송이 가능함을 보였다.

• 한국전기전자재료학회논문지
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• 제13권1호
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• pp.47-51
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• 2000

To make a practical application of a micro-strain sensors with ultrahigh sensitivity, a strain on electrical properties of micro-patterned amorphous (Fe\ulcornerco\ulcorner)\ulcornerSi\ulcornerB\ulcorner films had influenced on the impedance over frequency range from 1 MHz to 1 GHz. Reflecting excellent magnetomachanical couping properties of films, high frequency impedance was subject to change sensitively by a strain : a change in impe-dance of 39% was observed at 200 MHz applied a strain of 224$\times$10\ulcorner. To determine a optimum shape of micro-patterned films, film impedance was analyzed by virtue of its constitutive components of resis-tance and reactance. Result was shown that reduction of the resistance term(hence increase of resultant reactance term) of impedance is more effective for enhancing the strain sensitivity of films at relatively low frequency range.

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.780-784
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• 2006

We present high aspect ratio air-core solenoid inductors with $100{\mu}m\;and\;200{\mu}m$ tall via structures on Pyrex wafer. The effect of various parameters such as different number of turns, via heights, pitch distance between turns on inductor's radio frequency (RF) characteristics have been studied. The highest Q factor we obtained from various solenoid inductors is 72.8 at 9.7 GHz, which was produced by a 3-turn inductor.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.220-225
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• 1998

레이다를 이용한 콘크리트 구조믈의 지진으로 인한 손상도를 파악하기 위해, 콘크리트의 전자기적 특성(dielectric properties)을 레이다 작용 주파수 대역인 200MHz에서 6GHz 영역까지 측정하였다. 이의 측정을 위해 실험실에서 콘크리트의 전자기적 특성 계측을 가능하게 하는 회로망분석기(network analyser)를 사용하였다. 콘크리트의 전자기적 특성은 open-ended coaxial probe를 회로망 분석기에 연결하여 측정하였고, 실험전 측정값을 보정(calibration)하는 기법을 찾아내었다. 주파수의 변화와 함께 콘크리트 시편안에 포함된 수분의 양을 조절함으로써, 실제 콘크리트 구조물이 가질 수 있는 상태를 시편을 통해 측정하였다. 측정결과는 콘크리트의 전자기적 특성이 주파수와 수분함량에 따라 변하는 것을 보여주었으며, 이는 레이다를 이용한 콘크리트 구조물의 지진 손상도 파악 방법 개발에 필요한 자료를 제공하였다.

• 전자공학회논문지D
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• 제35D권3호
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• pp.56-62
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• 1998

One of the key components to accomplish WDM all-optical network is an arrayed waveguide grating router. The spectral characterisitc of the ypeical arrayed waveguide grating rouger has parabolic shape, hence the bandwidth is limited. The spectral response of an optical filter should be as flat as possible for the reliable operation of the syste, because the center frequency of the optical source could be deviated in the actual system. In order to acquire these characteristics, we propose and design a new type of the arrayed waveguide grating router with a flat passband using the Fourier optics concept. The BPM simulation results of the new arrayed waveguide grating router with the flat passband show that the bandwideth is 0.8 nm at -1 dB, instertion loss about 6 dB, and the crosstalk less than -23 dB fro each cnannel, which is 1.6 nm(200 GHz) separated from the adjacent channel around 1550 nm wavelength range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.191-192
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• 2007

This paper presents a 900MHz fractional-N frequency synthesizer for radio frequency identification (RFID) reader using $0.18{\mu}m$ standard CMOS process. The IC meets the EPC Class-1 Generation-2 and ISO-18000 Type-C standards. To minimize VCO pulling, the 900MHz VCO is generated by a 1.8GHz VCO followed by a frequency divider. The settling time of the synthesizer is less than $20{\mu}m$. The frequency synthesizer achieves the phase noise of -105.6dBc/Hz at 200kHz offset. The frequency synthesizer occupies an area of $1.8{\times}0.99mm^2$, and dissipates 8mA from a low supply voltage of 1.8V.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.306-309
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• 2000

The conductive polymers, polyaniline (PANI) emeraldine base and 3, 4-polyethylene dioxythiophene (PEDOT) were synthesized and coated on the PET film primer-dealt with acryl type to find out the electromagnetic shielding effectiveness. When conductive polymer such as PANI and PEDOT is used, if the thickness of coating increases then the electromagnetic shielding effectiveness increases, too, but the visible light transmittance decreases. For PANI, when its conductivity increased, its electromagnetic shielding effectiveness increased, too. For PANI, if the surface resistance is about 140 $\Omega$/$\square$, the shielding effectiveness is about 11 dB in the far field, and about 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance is about 200 $\Omega$/$\square$, the shielding effectiveness is about 3 dB.