Radio frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to power the next-generation wireless networks As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality-of-service requirements In this paper, we present a comprehensive literature review on the research progresses in wireless networks with RF energy harvesting capability, which is referred to as RF energy harvesting networks (RF-EHNs) First, we present an overview of the RF-EHNs including system architecture, RF energy harvesting techniques, and existing applications Then, we present the background in circuit design as well as the state-of-the-art circuitry implementations and review the communication protocols specially designed for RF-EHNs We also explore various key design issues in the development of RF-EHNs according to the network types, ie, single-hop networks, multiantenna networks, relay networks, and cognitive radio networks Finally, we envision some open research directions

Wireless Networks With RF Energy Harvesting: A Contemporary Survey

The aim of this paper is to show the possibility to harvest RF energy to supply wireless sensor networks in an outdoor environment. In those conditions, the number of existing RF bands is unpredictable. The RF circuit has to harvest all the potential RF energy present and cannot be designed for a single RF tone. In this paper, the designed RF harvester adds powers coming from an unlimited number of sub-frequency bands. The harvester’s output voltage ratios increase with the number of RF bands. As an application example, a 4-RF band rectenna is designed. The system harvests energy from GSM900 (Global System for Mobile Communications), GSM1800, UMTS (Universal Mobile Telecommunications System) and WiFi bands simultaneously. RF-to-dc conversion efficiency is measured at 62% for a cumulative ${-}{\hbox{10}}$ -dBm input power homogeneously widespread over the four RF bands and reaches 84% at 5.8 dBm. The relative error between the measured dc output power with all four RF bands on and the ideal sum of each of the four RF bands power contribution is less than 3%. It is shown that the RF-to-dc conversion efficiency is more than doubled compared to that measured with a single RF source, thanks to the proposed rectifier architecture.

A Multi-Band Stacked RF Energy Harvester With RF-to-DC Efficiency Up to 84%

This review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm2, volume of 2.88 cm3): ~300 µW from a light intensity of 1000 lx; (2) thermoelectric harvester (volume of 1.4 cm3): 6 mW from a thermal gradient of 25 °C; (3) periodic kinetic energy harvester (volume of 0.15 cm3): 2 µW from a vibration acceleration of 0.25 m s−2 at 45 Hz; (4) electromagnetic wave harvester (13 cm antenna length and conversion efficiency of 0.7): 1 µW with an RF source power of −25 dBm; and (5) airflow harvester (wind turbine blade of 6 cm diameter and generator efficiency of 0.41): 140 mW from an airflow of 8 m s−1. These results highlight the high potential of energy harvesting technology in buildings and the relative attractions of various harvester technologies. The harvested power could either be used to replace batteries or to prolong the life of rechargeable batteries for low-power (~1 mW) electronic devices.

http://iopscience.iop.org/article/10.1088/0957-0233/25/1/012002/pdf

Review of the application of energy harvesting in buildings

This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

This work addresses design and implementation issues of a 24 GHz rectenna, which is developed to demonstrate the feasibility of wireless power harvesting and transmission (WPT) techniques towards millimeter-wave regime. The proposed structure includes a compact circularly polarized substrate integrated waveguide (SIW) cavity-backed antenna array integrated with a self-biased rectifier using commercial Schottky diodes. The antenna and the rectifier are individually designed, optimized, fabricated and measured. Then they are integrated into one circuit in order to validate the studied rectenna architecture. The maximum measured conversion efficiency and DC voltage are respectively equal to 24% and 0.6 V for an input power density of 10 mW/cm
 2
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A High-Efficiency 24 GHz Rectenna Development Towards Millimeter-Wave Energy Harvesting and Wireless Power Transmission

RF energy is widely available in urban areas and thus presents a promising ambient energy harvesting source. In this paper, a CMOS harvester circuit is modeled and analyzed in detail at low environmental power levels. Based on the circuit analysis, a design procedure is given for a narrowband energy harvester. The antenna and harvester co-design methodology is discussed to improve RF to DC energy conversion efficiency. We demonstrate that it is difficult to harvest RF energy over a wide frequency band if the ambient RF energy sources are weak, owing to the voltage requirements. Since most ambient RF energy lies in a few narrow bands, a dual/multi-band energy harvester architecture should be able to harvest much of the available RF energy. A dual-band CMOS energy harvester is designed and fabricated using an IBM 0.13 μm process. The simulated and measured results demonstrate a dual-band energy harvester that obtains over 9% efficiency for two different bands (around 900 MHz and around 1900 MHz) at an input power as low as -19.3 dBm. The DC output voltage of this harvester is over 1 V, which can be used to recharge the battery to form an inexhaustibly powered communication system.

An Antenna Co-Design Dual Band RF Energy Harvester

Past work on radio frequency (RF) energy harvester design mostly focused on harvesting RF energy in a single RF band [1, 2,] While a significant portion of RF energy is concentrated in the communication band around 900 MHz, there is also abundant RF energy present in the band covering 1800 MHz to 2100 MHz For example Li [2011] demonstrated the design and implementation of a dual band RF energy harvester chip that has two cascade voltage multipliers in parallel and can operate at 900 and 1900 MHz bands The chip can generate 12 V output DC voltage at 900 MHz for −19 dBm RF input power and 105 V output voltage at 2000 MHz for −18 dBm RF input power The RF energy conversion efficiency is ∼12% at 900MHz and ∼8% at 2000MHz which is comparable with its single band counterparts at both frequencies in the literature The design greatly increases the energy harvesting efficiency over two bands It is found that the input impedance of the chip is ∼ 50 ohm at 900 MHz, 26 ohm at 19 GHz, and 70+j10 ohm at 2 GHz To operate the harvester chip in two bands, the antenna is required to be matched to the chip impedance at 900 MHz for one band and at either 19 GHz or 2GHz for the other band

A planar dual-band antenna design for RF energy harvesting applications

Radio Frequency (RF) energy harvesting aims at collecting and converting ambient RF wave energy into storable electrical energy to power electronics The reported RF energy density in urban areas can be as high as 05μW/cm2 which corresponds to an input power level of 166 μW (−176 dBm) at 1800MHz [1] It is thus appealing to convert the RF energy in the environment into electrical energy and use it to directly power mobile devices, remote sensors data loggers, low power digital applications, or charge batteries [2] In comparison with conventional battery-based power sources, the RF energy as a source is ubiquitous and can be harvested wirelessly In addition, the harvesting of RF energy makes use of the amount of energy that will be otherwise wasted Therefore, it makes use of the RF energy more efficient and is an environmentally friendly practice

Antenna-coupled dual band RF energy harvester design

RF energy harvesting has been widely investigated as a promising method of providing power to passive wireless devices or recharging the battery used in such systems. The AC input signal which is the ambient RF radiation from the available ISM band is received through the coupled antenna and converted into DC output voltage through the energy harvester chip. The energy harvester, which is a novel resonant boost rectifier circuit, typically consists of multiple stages of voltage doubler stacked in series to achieve a desired output voltage level. In order to achieve maximum rectifier conversion efficiency, it is imperative to have impedance matching between the receiving antenna and the harvester circuit. The input of the harvester is frequently modeled as a resistance in parallel with a capacitance [1]. Therefore, a physical model-based derivation of the equivalent input resistance and capacitance of the rectifier is useful to design an appropriate matching network to resonate out the input capacitance and to match the input resistance to the radiation resistance of the antenna. This paper presents an analytical approach to derive the equivalent input impedance of a multistage voltage doubler circuit designed using short-channel diode-connected MOSFETs.

Negin Shahshahan

Papers

An Antenna Co-Design Dual Band RF Energy Harvester

A planar dual-band antenna design for RF energy harvesting applications

Antenna-coupled dual band RF energy harvester design

An analytical model to characterize the input stage of a MOSFET based RF energy harvester for improved impedance matching