Radio Frequency Energy Harvesting and Management for Wireless Sensor Networks

Radio Frequency (RF) Energy Harvesting holds a promising future for generating a small amount of electrical power to drive partial circuits in wirelessly communicating electronics devices. Reducing power consumption has become a major challenge in wireless sensor networks. As a vital factor affecting system cost and lifetime, energy consumption in wireless sensor networks is an emerging and active research area. This chapter presents a practical approach for RF Energy harvesting and management of the harvested and available energy for wireless sensor networks using the Improved Energy Efficient Ant Based Routing Algorithm (IEEABR) as our proposed algorithm. The chapter looks at measurement of the RF power density, calculation of the received power, storage of the harvested power, and management of the power in wireless sensor networks. The routing uses IEEABR technique for energy management. Practical and real-time implementations of the RF Energy using Powercast harvesters and simulations using the energy model of our Libelium Waspmote to verify the approach were performed. The chapter concludes with performance analysis of the harvested energy, comparison of IEEABR and other traditional energy management techniques, while also looking at open research areas of energy harvesting and management for wireless sensor networks.Comment: 40 pages, 9 figures, 5 tables, Book chapte

Architecture of Micro Energy Harvesting Using Hybrid Input of RF, Thermal and Vibration for Semi-Active RFID Tag

This research work presents a novel architecture of Hybrid Input Energy Harvester (HIEH) system for semi-active Radio Frequency Identification (RFID) tags. The proposed architecture consists of three input sources of energy which are radio frequency signal, thermal and vibration. The main purpose is to solve the semi-active RFID tags limited lifespan issues due to the need for batteries to power their circuitries. The focus will be on the rectifiers and DC-DC converter circuits with an ultra-low power design to ensure low power consumption in the system. The design architecture will be modelled and simulated using PSpice software, Verilog coding using Mentor Graphics and real-time verification using field-programmable gate array board before being implemented in a 0.13 µm CMOS technology. Our expectations of the results from this architecture are it can deliver 3.3 V of output voltage, 6.5 mW of output power and 90% of efficiency when all input sources are simultaneously harvested. The contribution of this work is it able to extend the lifetime of semi-active tag by supplying electrical energy continuously to the device. Thus, this will indirectly  reduce the energy limitation problem, eliminate the dependency on batteries and make it possible to achieve a batteryless device.This research work presents a novel architecture of Hybrid Input Energy Harvester (HIEH) system for semi-active Radio Frequency Identification (RFID) tags. The proposed architecture consists of three input sources of energy which are radio frequency signal, thermal and vibration. The main purpose is to solve the semi-active RFID tags limited lifespan issues due to the need for batteries to power their circuitries. The focus will be on the rectifiers and DC-DC converter circuits with an ultra-low power design to ensure low power consumption in the system. The design architecture will be modelled and simulated using PSpice software, Verilog coding using Mentor Graphics and real-time verification using field-programmable gate array board before being implemented in a 0.13 µm CMOS technology. Our expectations of the results from this architecture are it can deliver 3.3 V of output voltage, 6.5 mW of output power and 90% of efficiency when all input sources are simultaneously harvested. The contribution of this work is it able to extend the lifetime of semi-active tag by supplying electrical energy continuously to the device. Thus, this will indirectly  reduce the energy limitation problem, eliminate the dependency on batteries and make it possible to achieve a batteryless device

Hardware Architectures for Low-power In-Situ Monitoring of Wireless Embedded Systems

As wireless embedded systems transition from lab-scale research prototypes to large-scale commercial deployments, providing reliable and dependable system operation becomes absolutely crucial to ensure successful adoption. However, the untethered nature of wireless embedded systems severely limits the ability to access, debug, and control device operation after deployment—post-deployment or in-situ visibility. It is intuitive that the more information we have about a system’s operation after deployment, the better/faster we can respond upon the detection of anomalous behavior. Therefore, post-deployment visibility is a foundation upon which other runtime reliability techniques can be built. However, visibility into system operation diminishes significantly once the devices are remotely deployed, and we refer to this problem as a lack of post-deployment visibility

Asic Design of RF Energy Harvester Using 0.13UM CMOS Technology

Recent advances in wireless sensor nodes, data acquisition devices, wearable and implantable medical devices have paved way for low power (sub 50uW) devices. These devices generally use small solid state or thin film batteries for power supply which need replacement or need to be removed for charging. RF energy harvesting technology can be used to charge these batteries without the need to remove the battery from the device, thus providing a sustainable power supply. In other cases, a battery can become unnecessary altogether. This enables us to deploy wireless network nodes in places where regular physical access to the nodes is difficult or cumbersome. This thesis proposes a design of an RF energy harvesting device able to charge commercially available thin film or solid-state batteries. The energy harvesting amplifier circuit is designed in Global Foundry 0.13um CMOS technology using Cadence integrated circuit design tools. This Application Specific Integrated Circuit (ASIC) is intended to have as small a footprint as possible so that it can be easily integrated with the above-mentioned devices. While a dedicated RF power source is a direct solution to provide sustainable power to the harvesting circuit, harvesting ambient RF power from TV and UHF cellular frequencies increases the possibilities of where the harvesting device can be placed. The biggest challenge for RF energy harvesting technology is the availability of adequate amount of RF power. This thesis also presents a survey of available RF power at various ultra-high frequencies in San Luis Obispo, CA.The idea is to determine the frequency band which can provide maximum RF power for harvesting and design a harvester for that frequency band

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

Efficient power conversion interface circuits for energy harvesting applications

Harvesting energy from the environment for powering micro-power devices have been increasing in popularity. These types of devices can be used in embedded applications or in sensor networks where battery replacement is impractical. In this dissertation, different methods of energy harvesting from the environment are explored as alternative sources of energy for devices. Some of the most popular energy extraction used in electronic devices today are radio frequency (RF) and thermal/vibrational energy extraction. This dissertation presents novel power techniques that enable some of the most efficient power conversion circuits published to date. New power conversion circuits to interface to a piezoelectric micro-power generator that produces electrical energy from temperature differences have been fabricated and tested. Circuit designs and measurement results are presented for a half-wave synchronous rectifier with voltage doubler, a full-wave synchronous rectifier and a passive full-wave rectifier circuit. The active rectifier based on synchronous rectification, fabricated in a 0.25-μm CMOS process, is 86% efficient with 22-μW peak output power when connected to the piezoelectric micro-power generator. This gives the highest efficiency to date for active rectification circuits at the micro-power level. The passive rectifier circuit is 66% efficient with 16-μW peak output power and requires no quiescent current to operate. RF-powered devices are typically inductively coupled and extract their energy from the near field while operating within a few inches of the radiating source. Longer operating distances, exceeding 10 meters, are desired for a broader set of applications including distributed sensor networks. This dissertation describes an efficient method for far field power extraction from RF energy to enable long distance passively powered sensor networks. Passive rectifier circuits are designed in the TSMC 0.25μm mixed-signal CMOS process and antennas for the system are printed on a 4-layer FR4 board. A high-Q resonator is used with a matching network to passively amplify the input voltage to the rectifier. At the circuit level, floating gate transistors are used as rectifying diodes to reduce the diode threshold loss in voltage rectification and therefore increase the rectifier efficiency. A 36-stage rectifier fabricated in a 0.25-μm CMOS process attains an efficiency of over 60% in the far field with a received power sensitivity of 5.5μW(-22.6 dBm), corresponding to an operating distance of 44 meters. The effective threshold voltage of the floating-gate diode is reduced to 36 mV. This is the highest performance for far-field RF energy conversion reported to date. In ultra-low energy system, such as sensor networks, it is essential that power management circuitry are designed to dissipate very low quiescent power. RF energy and power management circuits are designed in a 0.18μm CMOS process. Voltage regulators are designed to operate at high input voltage and low power in a standard CMOS process. The voltage regulators can withstand input voltages up to 12 volts and dissipates from 90 nW to 1.4 μW of power. A floating-gate programming circuit is designed with a self-wakeup timer that turns itself on about once a month. The floating-gate programming circuits dissipates about 30 nW in sleep mode and 8 μW in active mode

RF Energy Harvesting Wireless Communication: RF Environment, Device Hardware and Practical Issues

Radio frequency (RF) based wireless power transfer provides an attractive solution to extend the lifetime of power-constrained wireless sensor networks. Through harvesting RF energy from surrounding environments or dedicated energy sources, low-power wireless devices can be self-sustaining and environment-friendly. These features make the RF energy harvesting wireless communication (RF-EHWC) technique attractive to a wide range of applications. The objective of this article is to investigate the latest research activities on the practical RF-EHWC design. The distribution of RF energy in the real environment, the hardware design of RF-EHWC devices and the practical issues in the implementation of RF-EHWC networks are discussed. At the end of this article, we introduce several interesting applications that exploit the RF-EHWC technology to provide smart healthcare services for animals, wirelessly charge the wearable devices, and implement 5G-assisted RF-EHWC