• Title/Summary/Keyword: RF energy transfer

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RF Energy Transfer Testbed Based on Off-the-shelf Components for IoT Application (IoT 응용을 위한 RF 에너지 전송 테스트베드 구현 및 실험)

  • Aziz, Arif Abdul;Tribudi, Dimas;Ginting, Lorenz;Rosyady, Phisca Aditya;Setiawan, Dedi;Choi, Kae Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.10
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    • pp.1912-1921
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    • 2015
  • In this paper, we introduce a testbed for testing the RF energy transfer technology in the Internet of Things (IoT) environment, and provide experimental results obtained by using the testbed. The IoT environment considered in this paper consists of a power beacon, which is able to wirelessly transfers energy via microwave, and multiple sensor nodes, which makes use of the energy received from the power beacon. We have implemented the testbed to experiment the RF energy transfer in such IoT environment. We have used off-the-shelf hardware components to build the testbed and have made the tesbed controlled by software so that various energy and data transmission protocol experiments can easily be conducted. We also provide experimental results and discuss the future research direction.

Physical Layer Secrecy Performance of RF-EH Networks with Multiple Eavesdroppers

  • Truong, Tien-Vu;Vo, Nhan-Van;Ha, Dac-Binh;Tran, Duc-Dung
    • Journal of information and communication convergence engineering
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    • v.14 no.3
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    • pp.171-176
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    • 2016
  • In this study, we investigate the physical layer secrecy performance of RF energy harvesting (EH) networks over Rayleigh fading channels. The RF-EH system considered here consists of one power transfer station, one source, one destination, and multiple passive eavesdroppers. The source harvests energy from the power transfer station and transmits the information to the destination by using a time switching-based relaying protocol. The eavesdroppers try to extract the transmitted information without an active attack. By using the statistical characteristics of the signal-to-noise ratio (SNR), the exact closed-form expressions of the existence probability of the secrecy capacity and the secrecy outage probability are derived. Further, we analyze the secrecy performance of the system with respect to various system parameters, such as the location of the system elements and the number of eavesdroppers. Finally, the equivalent Monte Carlo simulation results are provided to confirm the correctness of our calculations.

A scheme for efficient data transmission and energy harvesting in drone systems using time-power switching (Time-Power 제어를 이용한 드론의 효율적 데이터 전송 및 에너지 하비스팅 기법)

  • Hong, Seung Gwan;Cha, Gyeong Hyeon;Lee, Sun Yui;Hwang, Yu Min;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.10 no.4
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    • pp.71-76
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    • 2015
  • In this paper, we propose a system model which effectively transmits the data and conducts RF energy harvesting in a wireless communication network of LTE and 5G. Through time switching and power splitting schemes, we find a time & power ratio to show the good performance according to the standard that we set up for transmitting a signal and conducting RF energy harvesting. So selecting optimal time & power ratio, we can efficiently transfer data to other drones and harvest the amount of harvested power simultaneously we desire. Also, according to conducting the performance analysis, we can compare an ideal receiver with the proposed system model. And, we suggest a future direction of research.

A Novel Design of an RF-DC Converter for a Low-Input Power Receiver

  • Au, Ngoc-Duc;Seo, Chulhun
    • Journal of electromagnetic engineering and science
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    • v.17 no.4
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    • pp.191-196
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    • 2017
  • Microwave wireless power transmission (MWPT) is a promising technique for low and medium power applications such as wireless charging for sensor network or for biomedical chips in case with long ranges or in dispersive media such. A key factor of the MWPT technique is its efficiency, which includes the wireless power transmission efficiency and the radio frequency (RF) to direct current (DC) voltage efficiency of RF-DC converter (which transforms RF energy to DC supply voltage). The main problem in designing an RF-DC converter is the nonlinear characteristic of Schottky diodes; this characteristic causes low efficiency, higher harmonics frequency and a change in the input impedance value when the RF input power changes. In this paper, rather than using harmonic termination techniques of class E or class F power amplifiers, which are usually used to improve the efficiency of RF-DC converters, we propose a new method called "optimal input impedance" to enhance the performance of our design. The results of simulations and measurements are presented in this paper along with a discussion of our design concerning its practical applications.

Preparation of Al-Sn Coating Bearings by RF Sputtering Method and Evaluation of Their Properties (RF 스퍼터링법에 의한 Al-Sn계 코팅베어링의 제작과 특성 평가)

  • 이찬식;이명훈
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.6
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    • pp.139-146
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    • 2000
  • The development of high performance materials is very important subject in order to enhance the properties of bearings whose role is to transfer energy harmoniously by reducing the problem of friction and wear down, etc. between the interacting solid surfaces in relative motion under high loads in comply with mechanical operating mechanism of engines. In this study, several (100-x)Al-xSn coating films (where x=85, 75, 65 atomic % at Al) on substrates which are abt. 2mm thickenss of Kelmet layer sintered back steel were prepared by using RF sputtering system. These coating films were observed the morphology by SEM(Scanning Electron Microscope) and investigated the crystal structure by XRD(X-ray Diffractor) for their properties. And friction coefficient of these films was measured by ball-on-disc tester for their tribological properties. From the experimental results, it was shown that high performance properties of bearing can be improved greatly by controlling the composition and morphology of material surface with effective use of the plasma-assisted sputtering process.

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Development of Far Field RF Power Harvesting Testbed (원거리 무선 전력 하베스팅 테스트 시스템 개발)

  • Kim, Min Jae;Lim, Wonseob;Bae, Jongseok;Park, Ju Hyun;Park, Young Jun;Lee, Jong Min;Trinh-Van, Son;Kim, Dong In;Lee, Kang Yoon;Hwang, Keum Cheol;Yang, Youngoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.10
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    • pp.1922-1930
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    • 2015
  • This paper presents the system design, implement, and measurement results of the testbed for the wireless RF energy harvesting system. The developed testbed can be used for RF power transfer and data communication using the 2.4 GHz and 900 MHz frequency bands. It allows to evaluate the system performances for the RF power and data transmission. The testbed can also be used to develop algorithms for efficient energy harvesting.

Joint Routing, Scheduling, and Power Control for Wireless Sensor Networks with RF Energy Transfer Considering Fairness (무선 에너지 전송 센서망에서의 공평성을 고려한 라우팅, 스케줄링, 전력 제어)

  • Moon, Seokjae;Roh, Hee-Tae;Lee, Jang-Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.2
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    • pp.206-214
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    • 2016
  • Recently, radio frequency energy transfer (RFET) attracts more and more interests for powering sensor nodes in the wireless sensor network (WSN). In the conventional WSN, reducing energy consumption of sensor nodes is of primary importance. On the contrary, in the WSN with RFET, reducing energy consumption is not an important issue. However, in the WSN with RFET, the energy harvesting rate of each sensor node depends on its location, which causes the unbalanced available energy among sensor nodes. Hence, to improve the performance of the WSN with RFET, it is important to develop network protocols considering this property. In this paper, we study this issue with jointly considering routing, scheduling, and power control in the WSN with RFET. In addition, we study this issue with considering two different objectives: 'Max-min' with which we tries to maximize the performance of a sensor node having the minimum performance and 'Max-min fairness' with which we tries to achieve max-min fairness among sensor nodes. We show that our solutions can improve network performance significantly and we also discuss the differences between 'Max-min' and 'Max-min fairness'.

Array Topology of Microwave Wireless Power Transmission on Electronic Power System (전력계통 연계를 대비한 마이크로파 무선전력 송수신기 에레이 구성 고찰)

  • Lee, Dongho
    • 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.

Joint Optimization of Mobile Charging and Data Gathering for Wireless Rechargeable Sensor Networks

  • Tian, Xianzhong;He, Jiacun;Chen, Yuzhe;Li, Yanjun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.7
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    • pp.3412-3432
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    • 2019
  • Recent advances in radio frequency (RF) power transfer provide a promising technology to power sensor nodes. Adoption of mobile chargers to replenish the nodes' energy has recently attracted a lot of attention and the mobility assisted energy replenishment provides predictable and sustained power service. In this paper, we study the joint optimization of mobile charging and data gathering in sensor networks. A wireless multi-functional vehicle (WMV) is employed and periodically moves along specified trajectories, charge the sensors and gather the sensed data via one-hop communication. The objective of this paper is to maximize the uplink throughput by optimally allocating the time for the downlink wireless energy transfer by the WMV and the uplink transmissions of different sensors. We consider two scenarios where the WMV moves in a straight line and around a circle. By time discretization, the optimization problem is formulated as a 0-1 programming problem. We obtain the upper and lower bounds of the problem by converting the original 0-1 programming problem into a linear programming problem and then obtain the optimal solution by using branch and bound algorithm. We further prove that the network throughput is independent of the WMV's velocity under certain conditions. Performance of our proposed algorithm is evaluated through extensive simulations. The results validate the correctness of our proposed theorems and demonstrate that our algorithm outperforms two baseline algorithms in achieved throughput under different settings.

Millimeter Wave Energy Transfer based on Beam Steering (밀리미터파를 이용한 빔 조향 기반의 에너지 전송 기술)

  • Han, Yonggue;Jung, Sangwon;Lee, Chungyong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.4
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    • pp.10-15
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    • 2017
  • Feedback burden of a full-digital energy beamforming, which is known as the optimal precoding scheme for radio frequency (RF) energy transfer, is huge because it uses a vector quantization for a channel feedback. To reduce the feedback burden, we consider a beam steering based wireless energy transfer, which uses a scalar quantization. Researches related to the beam steering based wireless energy transfer have been studied in special channel model with an assumption of full channel state information at the transmitter. In this paper, we analyze the beam steering scheme compared with the full-digital energy beamforming for practical channel models with channel estimation errors. According to characteristics of the millimeter wave channel, the number of antennas of the base station and the user, the distance between them, and channel estimation errors, we simulate the performance of the beam steering scheme and analyze reasons why.