• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.5
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• pp.215-219
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• 2004

ZnO epitaxial films have been grown on a (0001)sapphire substrate by RF magnetron sputtering. The single crystalline ZnO films were grown at the condition of growth rate of about 0.1~0.2 $\mu\textrm{m}$/hr and the substrate temperature of $600^{\circ}C$. The film thickness was about 400~500 nm. The thin film quality and micro-structure have been evaluated by XRD and TEM observation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.94-101
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• 2009

This paper presents scalable modeling of spiral inductors for RFIC design based on $0.13{\mu}m$ RF CMOS process. For scalable modeling, several inductor patterns are designed and fabricated with variations of width, number of turns and inner radius. Feeding structures are optimized for accurate de-embedding of pad effects. After measuring the S parameters of the fabricated patterns, double-$\pi$ equivalent circuit parameters are extracted for each device and their geometrical dependences are modeled as scalable functions. The inductor library provides two types of models including standard and symmetric inductors. Standard and symmetric inductors have the range of $0.12{\sim}10.7nH$ and $0.08{\sim}13.6nH$ respectively. The models are valid up to 30GHz or self-resonance frequency. Through this research, a scalable inductor library with an error rate below 10% is developed for $0.13{\mu}m$ RF CMOS process.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.124-127
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• 2010

본 논문에서는 소형 SMD 솔레노이드 형태의 RF 칩 인덕터의 최적 구조를 도출하였다. $1.0\times0.5\times0.5mm^3$ 크기의 96% $Al_2O_3$ 코아는 $40{\mu}m$ 직경의 구리 코일을 4회 권선하여 8.57nH의 인덕턴스, 37.6의 품질계수와 6.05GHz의 SRF를 가진다. $40{\mu}m$ 직경의 구리 코일을 0.35mm 솔레노이드 길이로 중앙에 6회 권선하였을 경우가 250MHz11.2nH의 인덕턴스, 29.8의 품질계수와 5.6GHz의 SRF로 가장 우수하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.402-403
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• 2011

This paper has proposed a $0.13-{\mu}m$ CMOS RF Front-end transmitter for LTE-Advanced systems. The proposed RF Front-end supports a band 7 (from 2500 MHz to 2570 MHz) in E-UTRA of 3GPP. It can provide a maximum output power level of +10 dBm but it's a normal output power level is +0 dBm considering a low PAPR. The post-layout simulation results show that the quadrature up-conversion mixer and a driver amplifier consumes 14 mA and 28 mA from a 1.2 V supply voltage respectively, while providing a output power level of 0 dBm at the input power level of -13 dBm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.159-163
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• 2005

This paper gives characterization of ZnO thin film deposited by RF magnetron sputtering method, which is concerned in deposition process and device fabrication process, to fabricate solidly mounted resonator(SMR)-type film bulk acoustic resonator(FBAR). A piezoelectric layer of 1.1${\mu}{\textrm}{m}$ thick ZnO thin films were grown on thermally oxidized SiO$_2$(3000 $\AA$)/Si substrate layers by RF magnetron sputtering at the room temperature. The highly c-axis oriented ZnO thin film was obtained at the conditions of 265 W of RF power, 10 mtorr of working pressure, and 50/50 of Ar/O$_2$ gas ratio. The piezoelectric-active area was 50 ${\mu}{\textrm}{m}$${\times}$50${\mu}{\textrm}{m}$, and the thickness of ZnO film and Al-3 % Cu electrode were 1.4 ${\mu}{\textrm}{m}$ and 180${\mu}{\textrm}{m}$, respectively. Its series and parallel frequencies appeared at 2.128 and 2.151 GHz, respectively, and the qualify factor of the resonator was as high as 401.8$\pm$8.5.

• Journal of Ginseng Research
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• v.33 no.1
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• pp.8-12
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• 2009

A simple gradient HPLC method for rapid determination of major ginsenosides ($Rg_1$ and $Rb_1$) and unique ginsenoside (Rf) of Korean ginseng (Panax ginseng C.A. Meyer) was developed. Within 50min, three ginsenosides have been separated and identified on $\mu$-Bondapak $C_{18}$ column ($3.9{\times}300\;mm$, $10{\mu}m$) with gradient elution using water and acetonitrile as a mobile phase. The method was validated in terms of linearity, accuracy, and precision. The correlation coefficients ($r^2$) for calibration curves of ginsenosides were over 0.9997. The developed HPLC method was successfully applied to the analysis of ginseng samples and the recoveries of ginsenosides were in the range of $101.1{\sim}115%$ with RSD<3.2%. The developed method could be used for rapid evaluation of the ginsenosides $Rg_1$, $Rb_1$, and Rf.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.506-517
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• 2015

This paper presents a 1.248 Gb/s - 2.918 Gb/s low-power receiver MIPI-DigRF M-PHY with a fully digital frequency detection loop. MIPI-DigRF M-PHY should be operated in a very short training time which is $0.01{\mu}s$ the for HS-G2B mode. Because of this short SYNC pattern, clock and data recovery (CDR) should have extremely fast locking time. Thus, the quarter rate CDR with a fully digital frequency detection loop is proposed to implement a fast phase tracking loop. Also, a low power CDR architecture, deserializer and voltage controlled oscillator (VCO) are proposed to meet the low power requirement of MIPI-DigRF M-PHY. This chip is fabricated using a $0.11{\mu}m$ CMOS process, and the die area is $600{\mu}m{\times}250{\mu}m$. The power consumption of the receiver is 16 mW from the supply voltage of 1.1 V. The measured lock time of the CDR is less than 20 ns. The measured rms and peak jitter are $35.24ps_{p-p}$ and $4.25ps_{rms}$ respectively for HS-G2 mode.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.320-327
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• 2010

In this paper, electrostatically actuated direct contact type RF MEMS switches have been designed and demonstrated. As driving structures of the switch, cantilever, bridge, and torsion spring beam structures are used and the actuation voltage characteristics of the switches have been compared and discussed. The designed RF switches are fabricated with the surface micromachining technology using the electroplated gold and nickel structures. The characteristics of the fabricated switches are measured and analyzed. The switch, which is fabricated using the 510 ${\mu}m$-length bridge structure with the thickness of 1.5 ${\mu}m$, is actuated with 15 V driving voltage. The insertion losses are less than 0.2 dB over the measured frequency ranges from 0 to 20 GHz and the isolations are more than 30 dB.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.3
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• pp.51-57
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• 2010

A dual-mode direct conversion receiver is developed in $0.13\;{\mu}m$ RF CMOS process for IEEE 802.11n based wireless LAN and IEEE 802.16e based mobile WiMAX application. The RF receiver covers the frequency band between 2.3 and 2.7 GHz. Three-step gain control is realized in LNA by using current steering technique. Current bleeding technique is applied to the down-conversion mixer in order to lower the flicker noise. A frequency divide-by-2 circuit is included in the receiver for LO I/Q differential signal generation. The receiver consumes 56 mA at 1.4 V supply voltage including all LO buffers. Measured results show a power gain of 32 dB, a noise figure of 4.8 dB, a output $P_{1dB}$ of +6 dBm over the entire band.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1037-1041
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• 2001

Silicon diosixde thick film using silica optical waveguide cladding was fabricated by Plasma Enhanced Chemical Vapor Deposition (PECVD) method, at a low temperature (32$0^{\circ}C$) and from (SiH$_4$+$N_2$O) gas mixtures. The effects of deposition parameters on properties of SiO$_2$thick films were investigated by variation of $N_2$O/SiH$_4$flow ratio and RF power. As the $N_2$O/SiH$_4$flow ratio decreased, deposition rate increased from 2.9${\mu}{\textrm}{m}$/h to maximum 10.1${\mu}{\textrm}{m}$/h. As the RF power increased from 60 W to 120 W, deposition rate increased (5.2~6.7 ${\mu}{\textrm}{m}$/h) and refractive index approached at thermally grown silicon dioxide (n=1.46).