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Enhanced Passive RF-DC Converter Circuit Efficiency for Low RF Energy HarvestingChaour, Issam, Fakhfakh, Ahmed, Kanoun, Olfa 02 May 2017 (has links) (PDF)
For radio frequency energy transmission, the conversion efficiency of the receiver is decisive not only for reducing sending power, but also for enabling energy transmission over long and variable distances. In this contribution, we present a passive RF-DC converter for energy harvesting at ultra-low input power at 868 MHz. The novel converter consists of a reactive matching circuit and a combined voltage multiplier and rectifier. The stored energy in the input inductor and capacitance, during the negative wave, is conveyed to the output capacitance during the positive one. Although Dickson and Villard topologies have principally comparable efficiency for multi-stage voltage multipliers, the Dickson topology reaches a better efficiency within the novel ultra-low input power converter concept. At the output stage, a low-pass filter is introduced to reduce ripple at high frequencies in order to realize a stable DC signal. The proposed rectifier enables harvesting energy at even a low input power from −40 dBm for a resistive load of 50 kΩ. It realizes a significant improvement in comparison with state of the art solutions
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Enhanced Passive RF-DC Converter Circuit Efficiency for Low RF Energy HarvestingChaour, Issam, Fakhfakh, Ahmed, Kanoun, Olfa 02 May 2017 (has links)
For radio frequency energy transmission, the conversion efficiency of the receiver is decisive not only for reducing sending power, but also for enabling energy transmission over long and variable distances. In this contribution, we present a passive RF-DC converter for energy harvesting at ultra-low input power at 868 MHz. The novel converter consists of a reactive matching circuit and a combined voltage multiplier and rectifier. The stored energy in the input inductor and capacitance, during the negative wave, is conveyed to the output capacitance during the positive one. Although Dickson and Villard topologies have principally comparable efficiency for multi-stage voltage multipliers, the Dickson topology reaches a better efficiency within the novel ultra-low input power converter concept. At the output stage, a low-pass filter is introduced to reduce ripple at high frequencies in order to realize a stable DC signal. The proposed rectifier enables harvesting energy at even a low input power from −40 dBm for a resistive load of 50 kΩ. It realizes a significant improvement in comparison with state of the art solutions
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Efficiency Improvement of RF Energy Transfer by a Modified Voltage Multiplier RF DC ConverterChaour, Issam 22 March 2021 (has links)
Radio Frequency (RF) energy transfer is getting increasingly importance in new generations of wireless sensor networks and this trend is tremendously supported by the modern trends to Internet of things (IoT). This promising technology enables proactive energy replenishment for wireless devices. With RF energy, transmission long distances between the energy source and the receiver can be overbridged. The main challenge thereby is the power conversion efficiency from a low level RF input power to a Direct Current (DC) voltage which is able to supply the mobile system.
For this purpose, a novel approach for RF DC conversion is proposed. It consists of a modified voltage multiplier RF DC converter circuit by incorporating an inductor at the input of the circuit, which generates an induced voltage able to boost the output circuit and improve the conversion efficiency. Analytical analysis of the novel approach has been carried out to determine the optimal value of the inductor to maximize the output power. The experimental investigations show that the proposed solution is able to improve significantly both the output voltage and the power conversion efficiency, compared to the state of the art, and this especially at low input power ranges, which are often the case. At -10 dBm input power, the modified voltage multiplier RF DC converter circuit can reach 1.71 V output voltage and 49.21 % power conversion efficiency for, respectively, 500 kΩ and 10 kΩ resistive loads.
In order to validate the new proposal for the RF transfer system experimentally, microstrip meander line antennas and microstrip patch antenna arrays are designed for different ISM bands, where relevant requirements for RF energy transfer are respected. For each antenna a modified voltage multiplier RF DC converter circuit has been applied and the system is tuned to the corresponding resonant frequency to avoid mismatching. In this investigation several scenarios have been addressed, such as RF transmission energy, RF energy harvesting in Global System for Mobile (GSM) bands and Wireless Local Area Networks (WLAN) band are developed. Field test results show high performances of experimental results in comparison to the state of the art.:1 Introduction
2 Theoretical Background
3 State of the Art of RF Energy Transfer
4 Novel Approach for a RF DC Converter Circuit
5 Antennas Design
6 Experimental Verification at Specific Scenarios
7 Conclusion / Die RF-Energieübertragung (RF) gewinnt in neuen Generationen von drahtlosen Sensornetzen zunehmend an Bedeutung. Dieser Trend wird durch das Internet der Dinge (IoT) weiter unterstützt. Diese vielversprechende Technologie ermöglicht eine proaktive Energieversorgung für drahtlose Geräte. Mit RF-Energie können große Entfernungen zwischen der Energiequelle und dem Empfänger überbrückt werden. Die größte Herausforderung dabei ist der Wirkungsgrad, mit dem von einer niedrigen HF-Eingangsleistung in eine Gleichspannung (DC), mit welcher das mobile System versorgt wird, gewandelt wird.
Zu diesem Zweck wird ein neuer Ansatz für einen RF-DC-Wandler vorgeschlagen. Er besteht aus einer modifizierten Spannungsvervielfacher-RF-DC-Wandlerschaltung, die eine Spule am Eingang der Schaltung integriert. Diese erzeugt eine induzierte Spannung, die in der Lage ist die Ausgangsschaltung zu verstärken und den Umwandlungswirkungsgrad zu verbessern. Analytische Untersuchungen zu diesem neuartigen Ansatz wurden durchgeführt, um den optimalen Wert der Spule zu bestimmen und die Ausgangsleistung zu maximieren.
Die experimentellen Untersuchungen zeigen, dass die vorgeschlagene Lösung in der Lage ist, sowohl die Ausgangsspannung als auch den Wirkungsgrad der Leistungsumwandlung im Vergleich zum Stand der Technik deutlich zu verbessern. Dies gilt besonders für niedrige Eingangsleistungsbereiche, welche häufig vorkommen. Bei -10 dBm Eingangsleistung kann die modifizierte Spannungsvervielfacher-RF-DC-Wandlerschaltung 1.71 V Ausgangsspannung und 49.21 % Leistungswandlungswirkungsgrad für jeweils 500 kΩ und 10 kΩ ohmsche Last erreichen.
Um das neue RF-Übertragungssystem experimentell zu validieren, werden Mikrostreifenmäanderlinienantennen und Mikrostreifen-Patch-Antennenarrays für verschiedene ISM-Bänder ausgelegt, wobei die relevanten Anforderungen an die RF-Energieübertragung eingehalten werden. Für jede Antenne wurde eine modifizierte Spannungsvervielfacher-HF-DC-Wandlerschaltung verwendet und das System auf die entsprechende Resonanzfrequenz abgestimmt, um Fehlanpassungen zu vermeiden. Dabei wurden mehrere Szenarien untersucht, wie z.B. RF-Energieübertragung, RF-Energiegewinnung aus GSM-Bändern und WLAN-Netzwerken. Die Feldtests zeigen eine hohe Leistungsfähigkeit der experimentellen Ergebnisse im Vergleich zum Stand der Technik.:1 Introduction
2 Theoretical Background
3 State of the Art of RF Energy Transfer
4 Novel Approach for a RF DC Converter Circuit
5 Antennas Design
6 Experimental Verification at Specific Scenarios
7 Conclusion
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