Analysis of Magnetically-Coupled Loops Based On Characteristic Modes

[EN] A preliminary numerical magnetic field study of a wireless power transfer system composed of two interconnected source loops is addressed in this paper. The key feature of this study is to propose a new configuration capable of maintaining a uniform magnetic field density between the two loops. Furthermore, it has been shown that the Theory of Characteristic Modes is a helpful tool for investigating the near field of the magnetically-coupled loops.Abderrazak, F.; Antonino Daviu, E.; Ferrando Bataller, M.; Taldi, L. (2020). Analysis of Magnetically-Coupled Loops Based On Characteristic Modes. IEEE. 121-122. https://doi.org/10.1109/IEEECONF35879.2020.9329736S12112

A Transcutaneous Data and Power Transfer System for Osteogenesis Monitoring Sensors

Implant devices are widely used in health care applications such as life support systems, patient rehabilitation devices and patient monitoring devices. Medical implants have enabled physicians to obtain relevant real time information regarding an organ, or a site of interest with in the body and suggest treatment accordingly. In some cases, the position of the implant within the body or threats of infections prevents wired communication techniques to extract information from the implant. Wireless communication is the alternative in such cases. Distraction osteogenesis is one such application where wireless communication can be established with callus growth monitoring sensors to obtain bone growth data and activate distraction device. As a solution for wireless communication, the computational design, fabrication and testing of a spiral antenna that can operate in the 401-406 MHz Medical Implant Communication Services (MICS) band is detailed. The proposed system uses ZL70103 MICS band transceiver from Microsemi Corporation and enables wireless communication with the implant. Antenna is tested in an in-vivo system that makes use of biomimetic material and pig femur bone to mimic an application environment. Power requirements for the implant actuator system that performs distraction cannot be satisfied by a single battery. Percutaneous wires for powering the implant poses threats of infection and frequent surgeries for battery replacement alters patient’s immune systems. Wireless charging is viable solution in this case. A short range inductive power transfer system prototype is designed and tested on a custom testbed to analyze the power transfer efficiency with change in distance

Thermal and Mechanical Energy Harvesting Using Lead Sulfide Colloidal Quantum Dots

The human body is an abundant source of energy in the form of heat and mechanical movement. The ability to harvest this energy can be useful for supplying low-consumption wearable and implantable devices. Thermoelectric materials are usually used to harvest human body heat for wearable devices; however, thermoelectric generators require temperature gradient across the device to perform appropriately. Since they need to attach to the heat source to absorb the heat, temperature equalization decreases their efficiencies. Moreover, the electrostatic energy harvester, working based on the variable capacitor structure, is the most compatible candidate for harvesting low-frequency-movement of the human body. Although it can provide a high output voltage and high-power density at a small scale, they require an initial start-up voltage source to charge the capacitor for initiating the conversion process. The current methods for initially charging the variable capacitor suffer from the complexity of the design and fabrication process. In this research, a solution-processed photovoltaic structure was proposed to address the temperature equalization problem of the thermoelectric generators by harvesting infrared radiations emitted from the human body. However, normal photovoltaic devices have the bandgap limitation to absorb low energy photons radiated from the human body. In this structure, mid-gap states were intentionally introduced to the absorbing layer to activate the multi-step photon absorption process enabling electron promotion from the valence band to the conduction band. The fabricated device showed promising performance in harvesting low energy thermal radiations emitted from the human body. Finally, in order to increase the generated power, a hybrid structure was proposed to harvest both mechanical and heat energy sources available in the human body. The device is designed to harvest both the thermal radiation of the human body based on the proposed solution-processed photovoltaic structure and the mechanical movement of the human body based on an electrostatic generator. The photovoltaic structure was used to charge the capacitor at the initial step of each conversion cycle. The simple fabrication process of the photovoltaic device can potentially address the problem associated with the charging method of the electrostatic generators. The simulation results showed that the combination of two methods can significantly increase the harvested energy

Wireless Power Transfer to Biomedical Implants Using a Class-E Inverter and a Class-DE Rectifier

In this article, we propose a strategy for the design of a wireless power transfer system consisting of a class-E inverter, a half-bridge class-DE rectifier, and two coupled coils. The system is optimized for maximum power transfer efficiency. The design is validated via a case study, for which a wireless power transfer link to a neuroprosthesis was designed. After circuit simulations, a prototype was realized and measured. There is a good agreement between the calculated, simulated and measured voltages and currents. The prototype delivers 80 mW, 7 V to a biomedical implant at 6.78 MHz, the transfer efficiency is 52 to 68%, depending on the alignment. The end-to-end efficiency, with the controller and gate driver also taken into account, is 39 to 57%. Electromagnetic and thermal simulations were performed to verify compliance with relevant safety regulations on specific absorption rate (SAR) levels, magnetic field strength, and heat generation in the implant, for separation distances between the coils of 8 to 15 mm, and transverse misalignment from 0 to 15 mm.</p

Study of systems powered by triboelectric generators for bioengineering applications

Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2020-2021. Director: Pere Lluís Miribel Català. Co-director: Manel Puig i Vida

Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors

This reprint is a collection of the Special Issue "Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors" published in Nanomaterials, which includes one editorial, six novel research articles and four review articles, showcasing the very recent advances in energy-harvesting and self-powered sensing technologies. With its broad coverage of innovations in transducing/sensing mechanisms, material and structural designs, system integration and applications, as well as the timely reviews of the progress in energy harvesting and self-powered sensing technologies, this reprint could give readers an excellent overview of the challenges, opportunities, advancements and development trends of this rapidly evolving field

Self-rechargeable energizers for sustainability

Electrical energy generation and storage have always been complementary to each other but are often disconnected in practical electrical appliances. Recently, efforts to combine both energy generation and storage into self-powered energizers have demonstrated promising power sources for wearable and implantable electronics. In line with these efforts, achieving self-rechargeability in energy storage from ambient energy is envisioned as a tertiary energy storage (3rd-ES) phenomenon. This review examines a few of the possible 3rd-ES capable of harvesting ambient energy (photo-, thermo-, piezo-, tribo-, and bio-electrochemical energizers), focusing also on the devices' sustainability. The self-rechargeability mechanisms of these devices, which function through modifications of the energizers’ constituents, are analyzed, and designs for wearable electronics are also reviewed. The challenges for self-rechargeable energizers and avenues for further electrochemical performance enhancement are discussed. This article serves as a one-stop source of information on self-rechargeable energizers, which are anticipated to drive the revolution in 3rd-ES technologies

Numerical Investigation on Flat-Top Beam Arrays for Wireless Power Transfer in the Millimeter-Wave Range

This thesis aims to analyze a far-field WPT link at mm-Wave proposing a transmitter i.e. 10x10 planar dipole antenna array operating at 31 GHz that radiates a ‘flat-top beam’ for uniform power distribution on the receiver side. The proposed link's reception system is made up of a number of single patch antennas that are arranged in space to completely cover the area invested by the flat radiation. To investigate the behavior of the flat-top beam, two different excitation configurations (in terms of amplitude and phase) were applied. The two configurations were named “Configuration 1” (in which the excitation was applied in a 1-dimensional way) and “Configuration 2D” (which had the excitation applied in a 2-dimensional manner) and the flatness was optimized through amplitude and phase variation. The receiving system can be viewed as a DC combiner because each patch antenna has a separate rectifier circuit that can collect RF power and convert it to DC. All the DC contributions were summed to compare the RF to DC efficiency of the entire mm-Wave for the two flat-top configurations. After comparing the results at different distances between the transmitting array and the receiving system for the two configurations, it was found that configuration 1 produced better results in terms of RF-DC efficiency per patch element whereas, configuration 2D produced better overall results in terms of total rectified power by the receiving system because a large number of receiving antennas could be accumulated inside the area covered by the beam. The average RF-DC efficiency was almost constant for every receiving patch which was a consequence of constant received power which was achieved through the flat-top bea