Energy Harvesting with 2.45 GHz Rectenna for urban application

This paper describes the conception of a 2.45 GHz rectenna for energy harvesting application. Electromagnetic simulations have been carried out using Computer Simulation Technology software. The enhancement of the simulated output DC voltage is obtained with resonant circuit and Cockroft Walton boost (containing four zero bias diodes) for a sinusoidal input voltage. The simulated proposed rectenna with single zero-bias diode and RF-DC boosting circuit have been realized and measured inside an anechoic chamber. The behavior of measured plots is in accordance with the simulated ones. The simulated RF-DC boosting rectenna enhanced the output DC voltage up to 140 mV for 1 μW/cm 2 power density

A High-Efficiency Broadband Rectenna for Ambient Wireless Energy Harvesting

This paper presents a novel broadband rectenna for ambient wireless energy harvesting over the frequency band from 1.8 to 2.5 GHz. First of all, the characteristics of the ambient radio-frequency energy are studied. The results are then used to aid the design of a new rectenna. A novel two-branch impedance matching circuit is introduced to enhance the performance and efficiency of the rectenna at a relatively low ambient input power level. A novel broadband dual-polarized cross-dipole antenna is proposed which has embedded harmonic rejection property and can reject the second and third harmonics to further improve the rectenna efficiency. The measured power sensitivity of this design is down to -35 dBm and the conversion efficiency reaches 55% when the input power to the rectifier is -10 dBm. It is demonstrated that the output power from the proposed rectenna is higher than the other published designs with a similar antenna size under the same ambient condition. The proposed broadband rectenna could be used to power many low-power electronic devices and sensors and found a range of potential applications

Design of Rectenna using RF Harvesting for Batteryless IoT Sensors

In this paper, we propose a compact and highly efficient Rectenna design (rectifying antenna), operating on ISM band with the centre frequency of 2.4 GHz. A RF to DC conversion through Schottky diode (HSMS2860) is used to generate the dc voltage to operate a battery-less IoT Sensor for RF power harvesting using the designed Rectenna. We have achieved more than 80% efficiency through Advanced Design System (ADS-2016) simulation software at different power densities. Further a rectenna circuit is designed using RF to DC Schottky detector diode and a microstrip patch antenna. The rectenna circuit design is simulated through ADS 2016 simulation software. The Battery less sensor requires 2V- 2.5V dc voltage to perform an optimum performance. As per simulation and theoretical/practical modeling we have achieved more than 80% efficiency at single Schottky diode and its operating from 915 MHz to 5.8 GHz. Rectenna operates at lower power densities start from 0.4uW/cm. The proposed rectenna design is a possible candidate to be used as sensors/devices at frequency of 2.4GHz with current technologies e.g. ZigBee, Wi-Fi, BLE etc and future probable application could be long range radio sensor using the latest new generation LoRa technology its line of sight range between 10km-20km

Ambient RF energy harvesting and efficient DC-load inductive power transfer

This thesis analyses in detail the technology required for wireless power transfer via radio frequency (RF) ambient energy harvesting and an inductive power transfer system (IPT). Radio frequency harvesting circuits have been demonstrated for more than fifty years, but only a few have been able to harvest energy from freely available ambient (i.e. non-dedicated) RF sources. To explore the potential for ambient RF energy harvesting, a city-wide RF spectral survey was undertaken in London. Using the results from this survey, various harvesters were designed to cover four frequency bands from the largest RF contributors within the ultra-high frequency (0.3 to 3 GHz) part of the frequency spectrum. Prototypes were designed, fabricated and tested for each band and proved that approximately half of the London Underground stations were found to be suitable locations for harvesting ambient RF energy using the prototypes. Inductive Power Transfer systems for transmitting tens to hundreds of watts have been reported for almost a decade. Most of the work has concentrated on the optimization of the link efficiency and have not taken into account the efficiency of the driver and rectifier. Class-E amplifiers and rectifiers have been identified as ideal drivers for IPT applications, but their power handling capability at tens of MHz has been a crucial limiting factor, since the load and inductor characteristics are set by the requirements of the resonant inductive system. The frequency limitation of the driver restricts the unloaded Q-factor of the coils and thus the link efficiency. The system presented in this work alleviates the use of heavy and expensive field-shaping techniques by presenting an efficient IPT system capable of transmitting energy with high dc-to-load efficiencies at 6 MHz across a distance of 30 cm.Open Acces

A rectenna as energy source for wireless sensor nodes.

This paper presents the feasibility assessment for the adoption of a rectenna with basic structure elements as energy source in wireless sensor networks (WSN) nodes. For that matter, a rectenna that harvests energy from 2.45 GHz was designed by the application of a tuning technique on the dimensions of its elements. In the design, the CST Microwave Studio and a SPICE based software were used. The DC-DC boost converter was selected among several commercial options. The limitations of the rectenna were evaluated using the power consumption of different nodes. Results show that the total maximum conversion efficiency for the rectenna was 34.08% at 20 dBm. The distance ranges between the designed rectenna and the wireless energy source were from 0.03 m to 0.20 m in the indoor scenario and from 0.26 m to 2.03 m in the outdoor scenario. The rectenna can supply the required power for the nodes CC2538 and CC1350 in the full range of distances, but for the nodes Z1 and Sky the range of distances is reduced

Multi-service highly sensitive rectifier for enhanced RF energy scavenging

Due to the growing implications of energy costs and carbon footprints, the need to adopt inexpensive, green energy harvesting strategies are of paramount importance for the long-term conservation of the environment and the global economy. To address this, the feasibility of harvesting low power density ambient RF energy simultaneously from multiple sources is examined. A high efficiency multi-resonant rectifier is proposed, which operates at two frequency bands (478-496 and 852-869 MHz) and exhibits favorable impedance matching over a broad input power range (40 to 10 dBm). Simulation and experimental results of input reflection coefficient and rectified output power are in excellent agreement, demonstrating the usefulness of this innovative low-power rectification technique. Measurement results indicate an effective efficiency of 54.3%, and an output DC voltage of 772.8 mV is achieved for a multi-tone input power of '10 dBm. Furthermore, the measured output DC power from harvesting RF energy from multiple services concurrently exhibits a 3.14 and 7.24 fold increase over single frequency rectification at 490 and 860 MHz respectively. Therefore, the proposed multi-service highly sensitive rectifier is a promising technique for providing a sustainable energy source for low power applications in urban environments