Wireless Energy Harvesting Technology Research Articles

Energy self-sufficient, multi-sensory tool holder for sensitive monitoring of milling processes

Machining processes, especially milling, place several requirements on monitoring systems. Two prevalent ones are minimal implications towards the machine tool system and direct proximity to the machining zone to acquire high signal quality. Thereby, sensitive detection of even minor process alterations is enabled. This paper presents a suitable monitoring approach based on a sensory tool holder. An innovative wireless energy harvesting technology using spindle rotation is implemented. Obtained signal data for exemplary milling processes as well as corresponding signal analysis strategies are presented.

Target Localization and Power Allocation Using Wireless Energy Harvesting Sensors

As radio-frequency (RF) based wireless energy harvesting technology can provide remote and continuous power to low-power devices, e.g., wireless sensors, it may be a substitute for batteries and extend the lifetime of the wireless sensor networks. In this paper, we propose a wireless energy harvesting localization system (WEHLoc), which contains batteryless wireless sensors as anchors and an energy access point (E-AP) to transfer power to the anchors. We consider a passive target localization scenario, in which the anchors monitor the target and send the sensed ranging data back to the E-AP. Additionally, we formulate the optimal estimation accuracy problem which is a 0–1 mixed-integer programming problem and relates to the energy beam, target transmitted power, and deployed anchor density. Then, we develop the power allocation scheme of the E-AP to solve the objective. In order to reduce the complexity, we propose a heuristic method that converts the maximum estimation accuracy problem into the energy efficiency problem and use linear programming to solve them. The simulations demonstrate that WEHLoc can be massively deployed in a wide area, and the estimation error and the power consumption are relatively low.

A Ge-based Schottky diode for 2.45 G weak energy microwave wireless energy transmission based on crystal orientation optimization and Sn alloying technology

With the development of modern communication technology, unlimited energy harvesting technology has become more and more popular. Among them, the weak energy density wireless energy harvesting technology has broken through the limitations in traditional transmission lines and can use the “waste” energy in the environment, which has become very popular. The Schottky diode is the core device of the 2.45 G weak energy density wireless energy harvesting system, and its performance determines the upper limit of the system's rectification efficiency. From the material design point of view, using crystal orientation optimization technology and Sn alloying technology, we propose and design a Ge-based compound semiconductor with large effective mass, large affinity, and high electron mobility. On this basis, the device simulation tool is further used to set reasonable device material physical parameters and geometric structure parameters, and a Ge-based Schottky diode for 2.45 G weak energy microwave wireless energy transmission is realized. The simulation of the ADS rectifier circuit based on the SPICE model of the device shows that comparing with the conventional Schottky diode, the turn-on voltage of the device is reduced by about 0.1 V, the zero-bias capacitance is reduced by 6 fF, and the reverse saturation current is also significantly increased. At the same time, the designed new Ge-based Schottky diode is used as the core rectifier device to simulate the rectifier circuit. The results show that the new-style Ge-based Schottky diode is in the weak energy working area with input energy in a range of –10 — –20 dBm. The energy conversion efficiency is increased by about 10%. The technical solutions and relevant conclusions of this article can provide a useful reference for solving the problem of low rectification efficiency of the 2.45 G weak energy density wireless energy harvesting system.

Ultrasound-Induced Wireless Energy Harvesting: From Materials Strategies to Functional Applications.

Wireless energy harvesting represents an emerging technology that can be integrated into a variety of systems for biomedical, physical, and chemical functions. The miniaturization and ease of implementation are the main challenges for the development of wireless energy harvesting systems. Unlike most reported wireless energy harvesting technologies represented by electromagnetic coupling, the new generation of ultrasound-induced wireless energy harvesting (UWEH) that use propagating ultrasound waves to carry the available energy provides a strategy with higher resolution, deeper penetration, and more security, especially in nanodevices and implantable medical systems where a long-term stable power is required. Recently, advances in nanotechnologies, microelectronics, and biomedical systems are revolutionizing UWEH. In this article, an overview of recent developments in UWEH technologies that use a variety of material strategies and system designs based on the piezoelectric and capacitive energy harvesting mechanisms is provided. Practical applications are also presented, including wireless power for bio-implantable devices, direct cell/tissue electrical stimulations, wireless recording and communication in nervous systems, ultrasonic modulated drug delivery, self-powered acoustic sensors, and ultrasound-induced piezoelectric catalysis. Finally, perspectives and opportunities are also highlighted.

Ultrasound‐Induced Wireless Energy Harvesting for Potential Retinal Electrical Stimulation Application

AbstractRetinal electrical stimulation for people with neurodegenerative diseases has shown to be feasible for direct excitation of neurons as a means of restoring vision. In this work, a new electrical stimulation strategy is proposed using ultrasound‐driven wireless energy harvesting technology to convert acoustic energy to electricity through the piezoelectric effect. The design, fabrication, and performance of a millimeter‐scale flexible ultrasound patch that utilizes an environment‐friendly lead‐free piezocomposite are described. A modified dice‐and‐fill technique is used to manufacture the microstructure of the piezocomposite and to generate improved electrical and acoustic properties. The as‐developed device can be attached on a complex surface and be driven by ultrasound to produce adjustable electrical outputs, reaching a maximum output power of 45 mW cm−2. Potential applications for charging energy storage devices and powering commercial electronics using the device are demonstrated. The considerable current signals (e.g., current >72 µA and current density >9.2 nA µm−2) that are higher than the average thresholds of retinal stimulation are also obtained in the ex vivo experiment of an implanted environment, showing great potential to be integrated on implanted biomedical devices for electrical stimulation application.

M2M Communication Assessment in Energy-Harvesting and Wake-Up Radio Assisted Scenarios Using Practical Components.

Techniques for wireless energy harvesting (WEH) are emerging as a fascinating set of solutions to extend the lifetime of energy-constrained wireless networks, and are commonly regarded as a key functional technique for almost perpetual communications. For example, with WEH technology, wireless devices are able to harvest energy from different light sources or Radio Frequency (RF) signals broadcast by ambient or dedicated wireless transmitters to support their operation and communications capabilities. WEH technology will have increasingly wider range of use in upcoming applications such as wireless sensor networks, Machine-to-Machine (M2M) communications, and the Internet of Things. In this paper, the usability and fundamental limits of joint RF and solar cell or photovoltaic harvesting based M2M communication systems are studied and presented. The derived theoretical bounds are in essence based on the Shannon capacity theorem, combined with selected propagation loss models, assumed additional link nonidealities, diversity processing, as well as the given energy harvesting and storage capabilities. Fundamental performance limits and available capacity of the communicating link are derived and analyzed, together with extensive numerical results evaluated in different practical scenarios, including realistic implementation losses and state-of-the-art printed supercapacitor performance figures with voltage doubler-based voltage regulator. In particular, low power sensor type communication applications using passive and semi-passive wake-up radio (WuR) are addressed in the study. The presented analysis principles and results establish clear feasibility regions and performance bounds for wireless energy harvesting based low rate M2M communications in the future IoT networks.

Wireless energy harvesting: Empirical results and practical considerations for Internet of Things

The continuous growth of the Internet of Things (IoT) has led to the development of different types of wireless sensors that are used for monitoring and actuation, communicating with each other and with various infrastructures through the Internet. The long-term and self-sustainable operation of these wireless sensors is a key factor when designing networks using them. To prolong the lifetime of these sensors, various approaches that are capable of harvesting the required energy from various sources have been proposed over the last few years. Wireless Energy Harvesting (WEH) technology is one of them which shows promise in terms of availability, ease of implementation, and cost. We investigate the current status of WEH technology for IoT-enabled sensors. In particular, we evaluate the energy characteristics and operation of two types of environmental wireless sensors (one based on Bluetooth Low Energy (BLE) communication and the other on the UDP protocol) that are powered by a wireless energy harvesting element and operate in the IoT environment. Our literature review on WEH for IoT revealed that despite significant advances that have been made in the design and development of wireless power harvesting elements, achieving self-sustainable wireless sensors for IoT remains a significant challenge. Finally, we also highlight some research challenges of WEH for IoT that need to be addressed in the future.

Wireless-Powered Device-to-Device Communications With Ambient Backscattering: Performance Modeling and Analysis

The recent advanced wireless energy harvesting technology has enabled wireless-powered communications to accommodate wireless data services in a self-sustainable manner. However, wireless-powered communications rely on active RF signals to communicate and result in high power consumption. On the other hand, ambient backscatter technology that passively reflects existing RF signal sources in the air to communicate has the potential to facilitate an implementation with ultra-low power consumption. In this paper, we introduce a hybrid device-to-device (D2D) communication paradigm by integrating ambient backscattering with wireless-powered communications. The hybrid D2D communications are self-sustainable, as no dedicated external power supply is required. However, since the radio signals for energy harvesting and for backscattering come from the ambient, the performance of the hybrid D2D communications depends largely on environment factors, e.g., distribution, spatial density, and transmission load of ambient energy sources. Therefore, we design two mode selection protocols for the hybrid D2D transmitter, allowing a more flexible adaptation to the environment. We then introduce analytical models to characterize the impacts of the considered environment factors on the hybrid D2D communication performance. Together with extensive simulations, our analysis shows that the communication performance benefits from larger repulsion, transmission load, and density of ambient energy sources. Furthermore, we investigate how different mode selection mechanisms affect the communication performance.

Viability Bounds of M2M Communication Using Energy-Harvesting and Passive Wake-Up Radio

Techniques for wireless energy harvesting (WEH) are being emerged as a fascinating set of solutions to extend the lifetime of energy-constrained wireless networks. They are commonly regarded as a key functional technique for almost perpetual communications. With the WEH technology, wireless devices are able to harvest energy from, e.g., different light sources or RF signals broadcast by ambient/dedicated wireless transmitters to support their operation and communications capabilities. The WEH technology will have increasingly wider range of use in upcoming applications for, e.g., wireless sensor networks, machine-to-machine (M2M) communications, and the Internet of Things (IoT). In this paper, the usability and fundamental limits of solar cell or photovoltaic harvesting-based M2M communication systems are studied and presented. The derived theoretical bounds are in essence based on the Shannon capacity theorem, combined with selected propagation loss models, assumed additional link nonidealities, as well as the given energy harvesting and storage capabilities. Fundamental performance limits and available capacity of the communicating link are derived and analyzed, together with extensive numerical results evaluated in different practical scenarios, including realistic implementation losses and the state-of-the-art printed supercapacitor performances. In particular, low-power sensor-type communication applications using passive wake-up radio (WuR)-assisted operation are addressed in this paper. The results show the benefits of using passive WuR, especially when the number of nodes is small. Moreover, the presented analysis principles and results establish clear feasibility regions and performance bounds for WEH-based low rate M2M communications in the future IoT networks.