Wirelessly Powered Passive Systems With Dynamic Energy Storage Mechanism

Safarian, Z.; Hashemi, Hossein

doi:10.1109/tmtt.2014.2304713

Cited by 21 publications

(7 citation statements)

References 23 publications

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“…Due to the presence of reflected wave, the power of the transmission line terminal can't be absorbed by the load. In order to improve the transmission efficiency, the voltage reflection coefficient S (1,1) is used to measure the degree of impedance matching [18], [19], Figure 8 shows the voltage reflection coefficient S (1,1) is −28.09dBm. Therefore, S (1,1) as the characteristics of return loss, the smaller value of which the reflection energy is more smaller and the energy transferred is greater.…”

Section: B Matching Circuitmentioning

confidence: 99%

A RF Energy Supply Method for End Nodes in Smart Buildings

Chai

et al. 2019

IEEE Access

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The application of Internet of Things in smart buildings is becoming more and more extensive. The energy supply problem of end nodes has always been a concern of the field of research and industry areas, and an adaptive radio frequency energy conversion system is proposed for the low power node of the Internet of Things. By using the unipolar transistor control, the threshold voltage of the rectifier changes dynamically, through RF matching, and double voltage rectification measures the supply for the low power nodes. The proposed circuit is aimed at reducing the threshold voltage of the transistor forward bias to increase power and output voltage of the harvester and increasing the reverse bias of the threshold voltage for reducing the leakage current. It prevents the loss of stored energy. This paper presents a 12 stages adaptive thresholdcompensated rectifier circuit has reached the maximum power conversion efficiency 35.3% at −14 dBm. Meanwhile, when the input power is −12dBm, the output voltage is 3.2 V at the output load 1 M. The low power characteristics of the nodes at the end of the Internet of Things make it possible to convert the RF energy into electric energy. INDEX TERMS Low power node, smart building, radio frequency energy harvester, energy conversion efficiency.

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Section: B Matching Circuitmentioning

confidence: 99%

A RF Energy Supply Method for End Nodes in Smart Buildings

Chai

et al. 2019

IEEE Access

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“…A full-bridge differential rectifier that can achieve close to 80% PCE [6], [8], [10], [24] is used in this design. It rectifies the AC RF voltages and therefore makes the load current unidirectional as shown with the schematic and conceptual timing diagram in Fig.…”

Section: A Rectifiermentioning

confidence: 99%

“…However, the PCE decreases once the input power becomes too large. This is due to the fact that the cross-coupled structure for both NMOS and PMOS renders itself to reverse current [10], [24]. As indicated in the timing diagram of Fig.…”

Section: A Rectifiermentioning

confidence: 99%

An RF Energy Harvester With 44.1% PCE at Input Available Power of -12 dBm

Hsieh

Chou

Chiang

2015

IEEE Trans. Circuits Syst. I

100

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A 900-MHz radio-frequency energy harvester is designed and implemented for remotely powered devices. An efficient power path structure with adaptive control is proposed to maintain close-to-optimal power conversion efficiency. The control circuit consumes low power by adopting a novel open-loop asynchronous implementation and duty-cycled operation. A startup circuit is also presented. Measurement results show minimum input available power for startup of 17 dBm. With input available power of 12 dBm and load resistance of 144 , the measured output power is 27.8 , giving an output voltage of 2 V. This corresponds to an end-to-end power conversion efficiency of 44.1%. The harvester consumes quiescent current of 1.56 at output voltage of 2 V.Index Terms-DC-DC boost converter, energy harvesting, full-bridge differential rectifier, passively powered device, power conversion efficiency, radio-frequency energy harvesting, remotely powered device, wireless sensor network, wireless sensor node. 1549-8328

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“…Compared to different types of energy sources, radio frequency (RF) energy harvesting provides relieved installation constraints (Hsieh et al , 2015). It can be used in RF identification (RFID) systems, wireless sensor nodes and biomedical implants (Safarian and Hashemi, 2014). A WPT system consists of a base station as an RF source and one or more sensor nodes.…”

Section: Introductionmentioning

confidence: 99%

“…Its impedance also changes with the variation of the output DC voltage level (Stoopman et al , 2014), (Shieh and Kamarei, 2016). Some works have focused on the matching network and have attempted to optimize it (Hsieh et al , 2015; Safarian and Hashemi, 2014; Stoopman et al , 2014; Shieh and Kamarei, 2016; Olgun et al , 2011; Li et al , 2013; Le et al , 2008; Abouzied and Sánchez-Sinencio, 2015; Papotto et al , 2011). But many of them modeled the rectifier with a fixed parallel resistance–capacitance (RC) circuit and found the optimum matching point using an iterative design methodology (Papotto et al , 2011) or extensive simulations (Le et al , 2008).…”

Section: Introductionmentioning

confidence: 99%

Frequency changing technique for efficient fast start-up RF energy harvesting

Shieh

Kamarei

2018

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Purpose The purpose of the paper is to present a frequency-changing technique to realize a fast start-up radio frequency (RF) energy harvester. Design/methodology/Approach First, a simple analysis of the input impedance of the rectifier circuit is presented, and based on the analysis, it is shown how the input impedance of the rectifier is changed during the rectifier charging. Then, the frequency-changing technique is presented in which the variation of the rectifier input reactance (capacitance) is partly compensated by changing the frequency of the transmitted RF signal. A harvester consisting of a four-stage rectifier and a simple series matching inductor, implemented based on Schottky diode, is employed to verify the technique. Findings With the input available power of −12 dBm, the simulated and the measured results prove that the proposed frequency-changing method compared to the typical fixed-frequency method shows more than 30 per cent decrease in the transient time to reach 0.5 V output voltage, while the final harvested output voltage is unchanged. Originality/Value A frequency-changing technique is presented.

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Wirelessly Powered Passive Systems With Dynamic Energy Storage Mechanism

Cited by 21 publications

References 23 publications

A RF Energy Supply Method for End Nodes in Smart Buildings

A RF Energy Supply Method for End Nodes in Smart Buildings

An RF Energy Harvester With 44.1% PCE at Input Available Power of -12 dBm

Frequency changing technique for efficient fast start-up RF energy harvesting

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