Diversity Combining for RF Energy Harvesting

RF energy harvesting (RFEH) is a promising technology for energy requirements of wireless communication nodes. However, providing sufficient amount of energy to ensure self-sufficient devices based on RFEH may be challenging. In this paper, the use of diversity combining in RFEH systems is proposed to increase the amount of harvested energy. The power consumption of diversity combining process is also taken into account to analyze the net benefit of diversity combining. Performances of RFEH systems are investigated for selection combining (SC), equal gain combining (EGC), and maximal ratio combining (MRC) techniques. Simulations are conducted to compare the numerical results of SC, EGC, and MRC, and the results show that although the diversity combining techniques can improve the energy harvesting performance, the power consumption parameters have a critical importance while determining the suitable technique

Analyse comportementale d'un circuit récupérateur d'énergie en présence de signaux complexes

International audienceThis paper shows the incidence of the modulation scheme and of the input power on the RF to DC rectifier conversion efficiency. A commercial energy harvesting (EH) P21XXCSR-EVB evaluation board from Powercast Corporation is used as measurement target and several waveforms are employed to evaluate the rectification efficiency. With a continuous wave as reference, QPSK, QAM and OFDM waveforms usage demonstrates that digital modulated signals can lead to a better efficiency. Thus, by selecting a high peak to average power ratio (PAPR), and under certain conditions, the performances of the energy harvesting circuit are enhanced.Cet article montre l'incidence du choix de la modulation et de la puissance du signal d'entrée sur l'efficacité d'une conversion RF-DC d'un circuit récupérateur d'énergie. Un circuit commercial de la société Powercast, le convertisseur P21XXCSR-EVB, est utilisé comme système récupérateur d'énergie RF et plusieurs formes d'onde sont générées afin de tester l'efficacité du redresseur. Avec comme référence une onde sinusoïdale, l'utilisation des formes d'ondes de type QPSK, QAM et OFDM montrent qu'un signal modulé permet d'atteindre une meilleure efficacité. Ainsi, en choisissant un rapport PAPR élevé, et sous certaines conditions, les performances du redresseur sont améliorées

Model and Analysis of Multi Level Multi Frequency RF Rectifier Energy System for Low Power Supply Application Device

Sustainable energy for the mobile electronic devices always needed during the energy storage batteries capacity in the mobile electronic devices are limited for a few hours for the usage time. To get a long lasting operating time from the mobile electronics equipment sets, the energy source should always be connected into the device. In this paper, we were proposed a charging energy method via wireless operation supply using the microwaves (RF) radiated by the air multi-frequency. The RF to DC rectifier circuit is a major component for changing the RF wave to an electronic current (DC). The Dickson models were used as an approach to superiority includes a simple series, low DC ripple factor, etc. The design, analysis, and the experimentation from the rectifier circuit have been conducted and presented in this paper. In the measurement, the mobile electronic devices placed at a distance about 5 meters from the energy source with the system voltage DC 3.7V, and have been obtained at the working frequency between 825 - 960MHz with the PCE values 12-33%, and a ripple factor of ± 0,01%. The charging time energy is needed about 4 hours at the research trial room, and about 11 hours outdoor had been observed. Based on these results, the wirelessly energy charging method for the mobile electronic devices is a potential methods to resolve the sustainable energy issue and the green technology supporting with the most programs.

Design of Wideband Antenna for RF Energy Harvesting System

This paper studies a wideband antenna of ice-cream cone structure and it is integrated with a rectifying circuit which has the potential to be used for RF energy harvesting system. The antenna is designed by using CST Studio Suite 2011 and fabricated on a double sided FR-4 printed circuit board using an etching technique. A single stage rectifying circuit is designed, simulated, fabricated and measured in this work. The design and simulation process was done by using Agilent Advanced Design System (ADS) 2011. Simulation and measurement were carried out for various input power levels at the specified frequency band. An experimental test has been conducted by varying the load, R of the rectifying circuit. For an equivalent incident signal of 20 dB, the system managed to produce 0.09V with load of 20k'. This voltage can be used to power low power sensors in sensor networks ultimately in place of batteries

Litar penuai tenaga hibrid mikro untuk aplikasi bioperubatan

Penggunaan penuai tenaga sebagai bekalan kuasa mendapat perhatian tinggi terutamanya untuk peranti berskala mikro. Ianya memanfaatkan sumber tenaga ambien untuk menghasilkan tenaga elektrik. Kajian yang mendalam telah dilakukan bagi memperolehi penuai tenaga dengan kecekapan dan kepekaan yang tinggi. Tiga sumber tenaga digunakan sebagai masukan iaitu tenaga haba, getaran dan Frekuensi Radio (RF). Masukan tenaga haba adalah dalam bentuk voltan DC manakala masukan getaran dan RF adalah dalam bentuk voltan AC. Kesemua masukan ini masing-masing ditetapkan pada nilai 0.02 V, 0.5 V dan -20 dBm. Frekuensi operasi yang digunakan bagi masukan getaran adalah 10 Hz manakala bagi masukan RF adalah 915 MHz. Litar penerus gelombang penuh digunakan bagi menukarkan isyarat getaran AC kepada DC. Sementara itu, litar pendarab voltan dibina dengan mengaplikasikan teknik modulasi substrat bagi menggandakan voltan masukan. Kesemua litar penuai tenaga tunggal ini digabungkan menggunakan litar penambah voltan untuk membentuk satu sistem penuai tenaga hibrid yang lengkap. Litar-litar penuai tenaga ini dibina dan disimulasi menggunakan perisian PSPICE dengan menyambungkan perintang beban 1 MΩ. Litar lengkap penuai tenaga dengan masukan hibrid berjaya mencapai voltan keluaran lebih kurang 2.12 V dan sesuai digunakan sebagai alternatif bekalan kuasa kepada aplikasi peranti bioperubatan. Peranti tersebut adalah Peranti Pemantau Kesihatan yang memerlukan bekalam masukan minimum 1.7 V

Resource Allocation Techniques for Wireless Powered Communication Networks with Energy Storage Constraint

This paper studies multi-user wireless powered communication networks, where energy constrained users charge their energy storages by scavenging energy of the radio frequency signals radiated from a hybrid access point (H-AP). The energy is then utilized for the users' uplink information transmission to the H-AP in time division multiple access mode. In this system, we aim to maximize the uplink sum rate performance by jointly optimizing energy and time resource allocation for multiple users in both infinite capacity and finite capacity energy storage cases. First, when the users are equipped with the infinite capacity energy storages, we derive the optimal downlink energy transmission policy at the H-AP. Based on this result, analytical resource allocation solutions are obtained. Next, we propose the optimal energy and time allocation algorithm for the case where each user has finite capacity energy storage. Simulation results confirm that the proposed algorithms offer 30% average sum rate performance gain over conventional schemes

Range Extension of Passive Wake-up Radio Systems through Energy Harvesting

Abstract—Use of a passive wake-up radio can drastically increase the network lifetime in a sensor network by reducing or even completely eliminating unnecessary idle listening. A sensor node with a wake-up radio receiver (WuRx) can operate in an extremely low power sleep mode until it receives a trigger signal sent by a wake-up radio transmitter (WuTx). After receiving the trigger signal, the attached WuRx wakes up the sensor node to start the data communication. In this paper, we implement and compare the performance of three passive wake-up radio-based sensor nodes: 1) WISP-Mote, which is a sensor mote that employs an Intel WISP passive RFID tag as the WuRx; 2) EH-WISP-Mote, which combines a novel energy harvester with the WISP-Mote; and 3) REACH-Mote, which uses the energy harvester circuit combined with an ultra-low-power pulse generator to trigger the wake-up of the mote. Experimental results show that the wake-up range and wake-up delay for the EH-WISP-Mote are improved compared with the WISP-Mote, while providing the ability to perform both broadcast-based and ID-based wake-ups. On the other hand, the REACH-Mote, which can only provide broadcast-based wake-up, can achieve a much longer wake-up range than any known passive wake-up radio to date, achieving feasible wake-up at a range of up to 37ft. I