• Journal of Advanced Marine Engineering and Technology
• /
• 제25권4호
• /
• pp.904-911
• /
• 2001

The fuels of water-in-oil emulsion have a potential of reducing PM(Particulate Matter) and NOx emissions, and increasing combustion efficiency in the furnaces and the burners. For making the most of the beneficial of the secondary atomization due to the microexplosion, the water droplets distributed in the oil must have the optimal sizes. The purpose of this paper is to investigate the water droplet size distribution characteristics of the different types of the static mixers. For analysis the size distribution characteristics efficiently, image analysis system wes constructed and an appropriate image processing algorithm was developed. Two kinds of static mixers: Kenics type and RF type, were tested. As a results, RF type static mixer shows a better characteristics in the mean drop size, particularly in the condition of high water content.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
• /
• pp.265-268
• /
• 2003

In RF application of resonator, cylinerical and transmission line(TRL) type are used generally, especially in ceramic modules the latter is used widely, TRL type resonators are used in VCO and RF filters etc.. TRL type resonators are divided stripline and microstripline and their characteristics depend on that of conductor and dielectric materials. In this study, the effect of material properties on the stripline resonator is measured and analyzed. Besides, the optimum design rule of resonator is presented.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.367-368
• /
• 2007

To investigate the 2nO thin films which are interested in the next generation of short wavelength LEDs and Lasers and UV photodetector with p-type inversion layer, the ZnO thin films were deposited by RF sputtering system. Gas ratios and work pressure is Ar : $O_2$ = 4 : 1 and 15 mTorr, respectively, and the purity of ZnO target is 5N. The ZnO thin films were deposited at 300, 450, and $650^{\circ}C$. The current-voltage, responsivity and quantum efficiency of devices were studied and compared with each devices.

• 한국전자파학회논문지
• /
• 제28권8호
• /
• pp.610-618
• /
• 2017

본 논문에서는 868/915 MHz 대역의 CMOS ZigBee RF 송수신기를 설계, 제작하였다. 무스위치 정합 네트워크를 이용하여 외부 스위치를 사용하지 않아 저가격화 실현이 가능하게 하였고, 스위치의 삽입 손실을 없애 RF 수신기의 잡음지수와 송신기의 출력전력 대비 전력소모에 이득을 가져올 수 있었다. 수신기는 저잡음 증폭기와 믹서, 기저대역 아날로그 회로로 구성되었고, 송신기는 기저대역 아날로그 회로, 믹서, 드라이버 증폭기로 구성되었으며, 주파수 합성기는 정수분주기 구조이다. 제안된 ZigBee RF 송수신기는 $0.18{\mu}m$ CMOS 공정 기술을 이용하여 단일칩 full transceiver 형태로 설계, 제작하었다. 측정 결과, 수신기의 최대 이득은 97.6 dB이고, 잡음지수는 6.8 dB이다. 수신 모드의 전류소모는 32 mA, 송신 모드의 전류소모는 33 mA이다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제49권5호
• /
• pp.283-288
• /
• 2000

In this work, small-size, high-performance simple solenoid-type RF chip inductors utilizing an Al2O3 core material were investigated. Copper (Cu) wire with $40\mum$ diameter was used as the coils and the size of the chip inductor fabricated in this work was $2.1mm\times1.5mm\times1.0mm$. The external current source was applied after bonding Cu coil leads to gold pads electro-plated on each end of backsides of a core material. High frequency characteristics of the inductance (L), quality factor (Q), and impedance (Z) of developed inductors were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). This HP4291B was also used to obtain the equivalent circuit and its circuit parameters of the chip inductors. This HP4291B was also used to obtain the equivalent circuit and its circuit parameters of the chip inductors. The developed inductors have the self-resonant frequency (SRF) of 1.1 to 3.1 GHz and exhibit L of 22 to 150 nH. The L of the inductors decreases with increasing the SRF. The Z of the inductors has the maximum value at the SRF and the inductors have the quality factor of 70 to 97 in the frequency range of 500 MHz to 1.5 GHz.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 C
• /
• pp.2052-2054
• /
• 2004

The TX/RX broadband L-type circular polarization antenna using LTCC at K/Ka band has been presented. This antenna has been analyzed in compensation for LTCC with relative permittivity 5.2 and could have been integrated with RF component. As the measured 10dB impedance circular polarization bandwidth of the proposed antenna is 7%(20.8GHz${\sim}$22.2GHz) at the K band and 2.3%(30.9GHz to 31.6GHz) at the Ka band. Also the gain of the antenna is -0.7${\sim}$3.05dBi at the K band and -2.8${\sim}$1dBi at the Ka band. The purpose of the research is to design an efficient antenna structure for satellite communication at K/Ka band. the antenna should be used for both TX and RX frequency bands. The antenna will be mounted on LTCC(Low Temperature Co-fired Ceramic) so that it can be integrated with other RF circuits. This research is important because of the following reasons. 1) The frequency ranges of satellite communication tends to move up to higher frequency such as Ka band or milimeter wave band. 2) Design of antenna for smaller size, lighter weight and less loss is preferred by most RF engineers. 3) Antennas on LTCC enables to integrate the antenna with other RF circuits, and thus, one can reduce the size and loss of the RF system.

• 디지털콘텐츠학회 논문지
• /
• 제18권7호
• /
• pp.1457-1464
• /
• 2017

본 논문에서는 UWB-RF를 이용하여 철근 콘크리트 구조물의 내부 물체 위치를 검출하고 모니터링 할 수 있는 시스템을 소개하고자 한다. 이 시스템은 콘크리트 내부 구조물의 변형을 매질에 대한 투과 특성 및 반사 특성을 이용하여 확인가능하며, 콘크리트 내부 구조물의 철근의 위치를 수치값으로 측정할 수 있다. 이 시스템의 성능을 검증하기 위해서 서로 다른 형태의 시편 3종에 대해서 콘크리트 내부 구성 상태를 분석하고, 구조물의 종류에 따라 측정되는 위치를 확인하기 위하여 구조물의 측정 거리 값을 소프트웨어로써 표현하였다. 그 결과 콘크리트 내에 구조물의 종류에 따라서 ${\pm}1{\sim}4mm$ 이내의 오차 내에서 측정할 수 있음을 확인하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권7호
• /
• pp.339-343
• /
• 2006

In this study, the variations of the important characteristics of solenoid-type RF chip inductors utilizing a low-loss A1203 core material on inductor dimensions were investigated systematically. Four dimensions of the chip inductors fabricated in this work were $1.0\times0.5\times0.5mm^3,\;1.5\times1.0\times0.7mm^3,\;2.1\times1.5\times1.0mm^3,\;and\;2.4\times2.0\times1.4mm^3$ and copper (Cu) wire with $40{\mu}m$ diameter was used as the coils. High frequency characteristics of the inductance, quality factor, and impedance of developed inductors as a function of inductor dimensions were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). It was observed that the developed inductors with the number of turns of 6 have the inductance (L) of 12 to 82 nH and exhibit the self-resonant frequency (SRE) of 3.6 to 1.2 GHz. The SRF of inductors decreases with increasing the inductor size while the L increases with the inductor size. The smallest inductors of $1.0\times0.5\times0.5mm^3$ exhibited the L of 12 nH, SRF of 3.6 GHz, and the quality factor of 67 near the frequency of 1.1 GHz. The calculated data predicted the high-frequency data of the L, and Q of the developed inductors well.

• 한국재료학회지
• /
• 제20권12호
• /
• pp.676-680
• /
• 2010

Most TCOs such as ITO, AZO(Al-doped ZnO), FTO(F-doped $SnO_2$) etc., which have been widely used in LCD, touch panel, solar cell, and organic LEDs etc. as transparent electrode material reveal n-type conductivity. But in order to realize transparent circuit, transparent p-n junction, and introduction of transparent p-type materials are prerequisite. Additional prerequisite condition is optical transparency in visible spectral region. Oxide based materials usually have a wide optical bandgap more than ~3.0 eV. In this study, single-phase transparent semiconductor of $SrCu_2O_2$, which shows p-type conductivity, have been synthesized by 2-step solid state reaction at $950^{\circ}C$ under $N_2$ atmosphere, and single-phase $SrCu_2O_2$ thin films of p-type TCOs have been deposited by RF magnetron sputtering on alkali-free glass substrate from single-phase target at $500^{\circ}C$, 1% $H_2$/(Ar + $H_2$) atmosphere. 3% $H_2$/(Ar + $H_2$) resulted in formation of second phases. Hall measurements confirmed the p-type nature of the fabricated $SrCu_2O_2$ thin films. The electrical conductivity, mobility of carrier and carrier density $5.27{\times}10^{-2}S/cm$, $2.2cm^2$/Vs, $1.53{\times}10^{17}/cm^3$ a room temperature, respectively. Transmittance and optical band-gap of the $SrCu_2O_2$ thin films revealed 62% at 550 nm and 3.28 eV. The electrical and optical properties of the obtained $SrCu_2O_2$ thin films deposited by RF magnetron sputtering were compared with those deposited by PLD and e-beam.

• 한국전자파학회논문지
• /
• 제13권10호
• /
• pp.1048-1053
• /
• 2002

본 논문에서는 2 GHz 대역의 격자형 및 평형 구조를 가지는 박막공진 여파기를 설계, 제작하고 분석하였다. 단위공진자의 앞전물질은 AIN를 사용하였고, 전극도체로는 백금을 사용하였으며, 하부도체와 기판사이에 공기층이 있는 구조로 제작되었다. 제작된 여파기들은 크기가 작고 낮은 삽입손실과 격자형의 경우 약 15 dB, 평형 구조의 경우 약 30 dB 정도의 선택도를 가진다. 격자형 및 평형 구조는 사다리형 구조와 같이 실리콘 기판위에 제작되었으며, 사다리형 구조에 비해 넓은 대역폭을 가지며 평형구조의 경우 이외의 튜닝과정 없이 RF 여파기로 사용될 수 있다.