• 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.17 no.5
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• pp.560-566
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• 2004

In this paper, the electrical and emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma (ICP) with the variation of argon gas pressure and RF power. The RF output was applied to the antenna in the range of 5∼50 W at 13.56 MHz. The internal plasma voltage of the chamber and the probe current were measured while varying the supply voltage to the Langmuir probe in the range of －100V∼＋100V. When the pressure of argon gas was increased, electric current was decreased. There was a significant electric current increase from 10 to 30 W. Also, when the RF power was increased, electron density was increased. Also, the emission spectrum, Ar- I lins, luminance were investigated. At this time, the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10∼60 mTorr, 10∼300 W, respectively. This implies that this method can be used to find an optimal RF power for efficient light illumination in an electrodeless fluorescent lamp.

• Nuclear Engineering and Technology
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• v.38 no.8
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• pp.779-784
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• 2006

The design, manufacturing process, and first operating test of a high power RF source for a proton accelerator are described. A klystron amplifier system has been developed for operation at 700 MHz, 1 MW and is composed of a triode type electron gun, six cavities, an RF output window, a beam collector, and an electromagnet. The prototype klystron was constructed and tested at a reduced duty to produce the designed output RF power.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.695-698
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• 2003

This paper presents a Si power LDMOSFET for power amplifiers in the 1.8-2.2GHz frequency range for the base station of personal communication systems. To improve the cut-off frequency, the proposed Si power LDMOSFET has small gate to drain capacitance by shielding the electric fields with extended source electrode and forming the field oxide structure in drain region. The proposed Si power LDMOSFET can be used for a power amplifier and it has 32% of power added efficiency and 39.5dBm of output power when the supply voltage is 28V and the operating frequency is 1.9GHz.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.275-280
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• 2006

We propose Doherty power amplifier structure which can be integrated in Silicon RF ICs. Doherty power amplifiers are widely used in RF transmitters, because of their high Power Added Efficiency (PAE) and good linearity. In this paper, it is proposed that a method to replace the quarter wavelength coupler with IQ up-conversion mixers to achieve 90 degree phase shift, which allows on-chip Doherty amplifier. This idea is implemented and manufactured in CMOS 5 GHz band direct-conversion RF transmitter. We measured a 3dB improvement output RF power and linearity.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.389-393
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• 2003

This paper describes the design of enhanced TSSI RF Power Detector which has wide dynamic range using switch and Log amp. This Power Detector consists of low and high gain loops, and they adaptively switched by output DC voltage which is proportioned to input power level. Because Power Detector needs to separate the channel, so architecture is heterodyne system having 70MHz intermediate frequency. This proposed RF Power Detector is settle to the satisfaction of Closed loop power control system for W-CDMA optic repeater, and the obtained dynamic range cover the higher than 50dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.779-787
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• 2017

In this paper, we designed a RF transceiver for small unmanned aerial vehicle(UAV) using power switching method. To apply for the UAV, several characteristics such as size, weight, and power consumption are very important. To reduce power consumption, we propose a new power switching method. Using the proposed method, we fabricated the RF transceiver needed to establish the data link for a small UAV. The fabricated RF transceiver shows an output power of +25 dBm, a noise figure of 4.56 dB and a received signal strength of -100 dBm. By performing power measurement of proposed switching method, 25 % of power could be reduced. The size of the fabricated RF transceiver is $100{\times}60{\times}5.7mm^3$ and the weight is as small as 38 g.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.99-104
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• 2013

In this paper, we developed a fully integrated downconverter MMIC (monolithic microwave integrated circuit) including Lange coupler and output active balun for millimeter wave applications. Concretely, ${\lambda}$/4 transmission line was added to Lange coupler for size reduction of RF/LO input, and mixed RF/LO signals were applied to gate of the FET of mixer. Active balun was used at output port for a coupling of out-of-phase IF output signals. According to measured results, the proposed downconverter MMIC showed good RF performances. For example, the downconverter MMIC showed an LO leakage power of -25 dBc at IF output port, and a RF-LO isolation of 18 dB. Therefore, off-chip components such as LO rejection filters were not required for a normal operation of the proposed downconverter MMIC. The proposed downconverter MMIC showed a conversion gain of 10.3 dB at RF frequency of 63 GHz. The size of the downconverter MMIC including all active and passive components was $2.2{\times}1.4mm^2$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1574-1579
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• 2016

This paper presents a self-powered sensor-node scheme using a RF wireless power harvesting techniques for improve drone time of flight. Sensor-node that is proposed is turned when two conditions satisfy: The one is input RF ID data from master-node should be same with sensor-node's ID, and the other one is RF wireless power harvesting system is turned on by hysteresis switch. In this paper, master-node's output is 26 dBm at 263 MHz. Maximum RF to DC power conversion efficiency is about 55% at 4-6 dBm input power condition (2 meter from master-node). The maximum RF wireless power harvesting range is about 13 meter form master-node. And power consumption of the sensor-node's load elements such as transmitter, MCU and temperature sensors is approximately average 15 mA at 5.0 V for 10 msec.

• Journal of IKEEE
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• v.27 no.1
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• pp.53-58
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• 2023

In this paper, a Radio Frequency (RF) transformer (TF) based on LTCC (Low Temperature Co-fired Ceramic) for the output stage of differential power amplifiers is presented. Instead of using an usual L-C matching circuit, a small-sized transformer was implemented on the LTCC board and the results were verified through simulation. For reduced size and better performance, a TF using more metal layers was implemented and compared with the existing TF through simulation. As a result of comparison, the proposed TF has an area reduced by 55% and a coupling coefficient increased by 25%, and insertion loss improvement of about 0.4dB at 5GHz was confirmed.