• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.111-114
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• 2001

Optical transmitter and receiver are the essential components for optical communication. For these components, butterfly type packages are used which are comprised of metal housing, multilayer ceramic inserts, lead and window. In this study, 2.5 Gbps DFB(Distributed -Feedback) LD(Laser Diode) package was fabricated and characterized. Metal housing showed good thermal conductivity (200W/mK) and well matched TCE(6.7ppm/K) with GaAs chip. Ceramic inserts also showed good VSWR(Voltage Standing Wave Ratio) characteristics(<2.0). By brazing technology, all the elements were combined and sealed. RF characteristics of the package mounted on the PWB was also tested.

• Progress in Superconductivity and Cryogenics
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• v.20 no.1
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• pp.23-27
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• 2018

As the wireless power transfer (WPT) technology based on strongly resonance coupled method realizes large power charging without any wires through the air, there are advantages compared with the wired counterparts, such as convenient, safety and fearless transmission of power. From this reason, the WPT systems have started to be applied to the wireless charging for various power applications such as train, underwater ship, electric vehicle. This study aims for the effect and characteristics of different inserted resonance coil between Tx and Rx coils for charging system of superconducting magnetic levitation (MAGLEV) train. The transfer efficiency and effect are evaluated with helix type, rectangular type copper resonance coil, and HTS resonance coil under bulb and HTS magnet load, respectively. The input power is adapted with radio frequency (RF) power of 370 kHz below 500 W.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.275-282
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• 2015

Recently, telemetry systems are used to test and evaluate of ammunition. When a transmitting signal from a small transmitter mounted inside the ammunition is sent out, the receiving equipments get real-time RF data. This paper relates to the development of a small high-G endurable transmitter and a portable receiving equipment. The system was tested and confirmed 00 km communication range.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.45-49
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• 2003

Wireless life signal detecting system is implemented with using the mechanism of Doppler Effect. This system can measure the respiration and heart rates with the periodic movement of skin and muscle near the heart. The system is consisted of antenna, RF transmitter, receiver, and display part. We did use two operating frequencies at 1.9 ㎓ and 10 ㎓. Firstly, the link budget about detecting system is analyzed and the signal detected from the system is compared with electrocardiogram(ECG) of monitor which is using for patient monitoring in hospital. Secondly, the detection of vital sign is also performed according to the different distances, and including behind the wall.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.423-426
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• 2007

An active Balun is designed for RFID reader at 2.45GHz. The Balun is integrated inside the receiver, then the LNA and mixer can be connected. The unbalanced LNA output signal is transformed to a balanced signal at the input mixer The RF mixer and LO mixer, by using this balun. The Balun provided a balanced signal with two output stage, gain mismatch is 0.116dB. The phase show a good behavior with $163.918^{\circ}$,$-16.609^{\circ}$. The phase mismatch is about $0.527^{\circ}$. The tight difference between the gain and phase on each brancd, is because of the used capacitor and integrated inductor and the other parasitic element inside the balun.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.97-100
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• 2009

The paper describes synchronization schemes for scalable video coding signals over the DVB-S2 network. The MPEG-4 SVC signals include a base layer signal and an enhancement layer signal. They are packetized into MPEG-2 transport streams and transmitted on separate RF channels through the DVB-S2 system. The DVB-S2 receiver is required to synchronize each layer signal together to recover the full pictures. Some new schemes to synchronize two. layered SVC signals in MPEG-4 SVC decoder are proposed and analyzed.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.449-454
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• 2012

According to the development of the ubiquitous computing technic today, the sensor base system is becoming a big issue in IT fields. This study is to develop a smart weather watching system which allows us to carry out temperature measuring without regard to location and altitude using the sensor devices. this system is composed of the wireless receiver module(PC base) and the wireless measuring module(ATmega2560 base).

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.1-10
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• 1998

A GaAs MMIC composed of VCO (voltage controlled oscillator) and mixer for PCS receiver has been developed using 1.mu.m ion implanted GaAs MESFET process. The VCO consists of a colpitts-type oscillator with a dielectric resonator and the circuit configuration of the mixer is a dual-gate type with an asymmetric combination of LO and RF FETs for the improvement of intermodulation characteristics. The common-source self-biasing is used in all circuits including a buffer amplifier and mixer, achieving a single power supply (3V) operation. The total power dissipation is 78mW. The VCO chip shows a phase noise of-99 dBc/Hz at 100KHz offset. The combined VCO/mixer chip shows a flat conversion gain of 2dB, the frequency-tuning factor of 80MHz/volts in the varacter bias ranging from 0.5V to 0.5V , and output IP3 of dBm at varactor bias of 0V. The fabricated chip size is 2.5mm X 1.4mm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.1889-1910
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• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.369-372
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• 2004

In this paper, a low noise amplifier (LNA) in receiver of Low Noise Block Down Converter (LNB) for direct broadcasting service (DBS) is implemented by using GaAs HEMT The LNA is designed for operation between 10.7GHz-12.7GHz. The LNA consists of input, output matching circuits, DC-blocks and RF-chokes. The result of simulation of the LNA shows that a noise figure is less than 1.4dB and a gain is gloater than 9.2dB in the bandwidth of 10.7 to 12.7GHz with good flatness of 0. ldB