• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.88-91
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• 2015

Wireless power transmission (WPT) is a technology using free space as a conductor for transmitting electric power, which aims to transfer not just the transmission signal but also the electrical energy itself. This paper takes issue with the microwave wireless transmission technology utilizing in long-distance transmission. To construct the WPT system, several components are needed, such as RF Oscillator which converts AC power to RF through DC status, high gain antenna and RF rectifier that converts RF back to DC. The array topology is good a candidate for wide use. The objective of this research is to study the efect of the WPT systmem on electric power system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.8
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• pp.610-618
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• 2017

This paper presents a 868/915 MHz CMOS RF transceiver for the ZigBee application. Using a switchless matching network, the off chip switch is removed to achieve the low cost RF transceiver, and by the elimination of the switch's insertion loss we can achieve the benefits for the RF receiver's noise figure and transmitter's power efficiency at the given output power. The receiver is composed of low-noise amplifier, mixer, and baseband analog(BBA) circuit. The transmitter is composed of BBA, mixer, and driver amplifier. And, the integer N type frequency synthesizer is designed. The proposed ZigBee RF full transceiver is implemented on the $0.18{\mu}m$ CMOS technology. Measurement results show that the maximum gain and the noise figure of the receiver are 97.6 dB and 6.8 dB, respectively. The receiver consumes 32 mA in the receiver mode and the transmitter 33 mA in the transmission mode.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.83-91
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• 2012

An RF energy detector for spectrum sensing in TV white space transceiver is presented. It is based on an RF active filtering technique that comprises a low-noise amplifier with a frequency-translation high-pass filtering feedfoward loop, which attenuates the unwanted sideband energy and only passes the wanted band energy. Unlike the conventional architecture, a new architecture that can attenuate both sidebands at the same time is proposed. A simplified system modeling method is presented to assess the non-ideality effects on the RF energy detector performances. System behavioral simulations demonstrate that the proposed architecture can be instrumental for realizaing a RF energy detector circuit in CMOS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1877-1882
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• 2013

Smart Utility Network (SUN) is not only a core technology of intelligent green home networks but also a future technology which can be applicable to various areas instead of ZigBee. SUN should be compliment with IEEE 802.15.4g standard and can provide high link margin and stable communication data-rate for poor communication surrounding. This paper describes how to design the system simulation environment for the SUN RF transceiver, and also reports the required block-level specification for each circuit and various implementation impairments. Finally, the measured performances of the fabricated RF transceiver, which has utilized the system simulation results, completely satisfies the IEEE 802.15.4g SUN PHY standard.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.36-44
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• 2016

In this paper, an Impulse Radio-Ultra Wide band RF Transceiver for WBAN applications is implemented in $0.18{\mu}m$ CMOS technology. The designed RF transceiver support 3-5GHz UWB low band and employs OOK(On-Off Keying) modulation. The receiver employs non-coherent energy detection architecture to reduce complexity and power consumption. For the rejection of the undesired interferers and improvement of the receiver sensitivity, RF active notch filter is integrated. The VCO based transmitter employs the switch mechanism. As adapt the switch mechanism, power consumption and VCO leakage can be reduced. Also, the spectrum mask is always same at each center frequency. The measured sensitivity of the receiver is -84.1 dBm at 3.5 GHz with 1.579 Mbps. The power consumption of the transmitter and receiver are 0.3nJ/bit and 41 mW respectively.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1406-1409
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• 2010

본 연구에서는 호출기를 착용한 환자가 낙상/전도 사고를 당했을 때, 자동으로 구조요청 하는 시스템을 개발하고자 한다. 자동 호출기에는 사고의 감지, 사고발생 위치의 추적, 관제센터로의 통신 등의 기능이 필요하다. 이를 위해 3축 가속도센서를 탑재하고, 낙상판단 알고리즘을 구현하여, MCU에 포팅하고, RF 송수신기와 알람을 집적하였다. 자동 호출기와 관제소와의 통신방법으로는 400MHz 대역의 RF 송수신기를 채택하였다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.200.1-200.1
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• 2012

저궤도 위성은 크게 탑재체(Payload) 와 본체(Bus System)로 구성된다. 버스시스템은 다시 여러 서브시스템으로 나뉘는데 그 중의 하나가 원격측정명령계이다. 원격측정명령계는 위성의 각 서브시스템에 대한 정보를 텔레메트리를 사용하여 지상으로 전송하고 지상으로부터 커맨드를 받아서 이에 대한 명령을 수행한다. 이 때 S 대역 송수신기를 통해 RF로 변복조 되어 지상과 통신을 하게 된다. 보통 저궤도 위성의 송수신기는 레인징 기능을 제공하는데 이는 위성의 궤도를 예측하는데 사용된다. 위성의 궤도를 예측하기 위해서는 위치를 알아야 하는데 이 때 지상국에서 일정한 톤 신호를 위성으로 보내 되돌아오는 신호를 측정하여 위상차를 통해 거리를 측정하게 된다. 위성에 탑재되는 송수신기는 설계상 고유의 레인징 신호 지연 값을 가지게 되는데 이는 위성 발사 후 위성과의 거리측정 시 계산에 영향을 미치게 된다. 때문에 이에 대한 정확한 값을 미리 획득하여 발사 후 위성 궤도 예측에 사용되어야 한다. 본 논문에서는 한국항공우주연원에서 개발한 저궤도 위성의 송수신기를 사용하여 정확한 레인징 측정방법을 통해 결과 값을 제시하여 레인징 성능을 확인하고 또한 장기간에 걸친 모니터링을 통해 경향을 파악하여 송수신기의 성능을 확인하여 추후 이를 지상국과 위성사이의 통신에 활용할 수 있게 한다.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.491-500
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• 2012

In this paper, a new loopback BIST structure which is effective to test RF transceiver chip and LNA(Low Noise Amplifier) in the chip is presented. Because the presented BIST structure uses a baseband processor in the chip as a tester while the system is under testing mode, the developed test technique has an advantage of performing test application and test evaluation in effectiveness. The presented BIST structure can change high frequency test output signals to a low frequency signals which can make the CUT(circuits under test) tested easily. By using this technique, the necessity of RF test equipment can be mostly reduced. The test time and test cost of RF circuits can be cut down by using proposed BIST structure, and finally the total chip manufacturing costs can be reduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.974-977
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• 2003

In this paper, the system that can be controlled in remote site by wireless data and video transceiver is represented. This system has functions and equipments such as video capturing and processing by CCTV camera, auto tracking for object, wireless video and data transceiver, Internet network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.808-814
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• 2007

In this paper, the measurement system of crane moving range is concerned with range recognition technology using phase and magnitude of radio wave. By the proposed technology, we design the radio transmitter and receiver and realize the measurement system, and save the data in disk that is earned from 900Mhz RF signal, middle frequency 450khz of analog signal. As a result of RF measurement, we got 9.3 dBm of RF output and 96 dBc@10khz of phase noise. Range information is earned the data through digital signal processing of IF signal. For the estimation of range measured, we analyze the difference between real range and measurement range, and also suggest the method to remove the measurement error using average processing and amplitude properties. A result is 0.12 and 0.00422 deviation in l0mn-30m and within 5m respectively, and then 2.4E-04 deviation in 4m by using compensation of level characteristics lately.