15 research outputs found

    Wirelessly-Powered CMOS Front End for Locomotive IC Applications

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    The steady leaps in miniaturization made in the realm of integrated circuit (IC) design has opened up prospects for a vast number of interesting possibilities. One of the possibilities is the idea of a locomotive integrated circuit. Unlike a typical IC that is soldered on a printed circuit board (PCB), locomotive ICs can be untethered and free to move around its environment. Recent research has demonstrated locomotive ICs that can potentially be used for non-invasive medical procedures including precise drug delivery targeted to specific problematic region of the body. Recent research has demonstrated locomotion using a variety of schemes including using electrolytic bubbles and manipulation of Lorentz force in a uniform magnetic field. In this work a wireless front end for a locomotive IC that relies on surface acoustic wave (SAW) devices is explored. A SAW device is a piezoelectric material that converts electrical stimulus into mechanical vibrations. For this work, the SAW device has been designed specifically to enable the mechanical vibration generated by electrical stimulation at 177MHz to potentially actuate motion. This work demonstrates a complementary metal-oxide semiconductor (CMOS) front end IC implemented in 180nm process that can potentially be used for locomo-tion by means of electrical excitation of a SAW device with an on-chip PLL frequency synthesizer. The energy required to power the IC is obtained through resonant wire-less power transfer between a pair of PCB inductor coils. The IC also contains power conditioning blocks that rectify the alternating voltage across the receiver inductor coil and generates a regulated DC voltage that powers the PLL frequency synthe-sizer. The entire proposed locomotive system consisting of PCB receiver coil, CMOS IC and SAW device fits inside an area of 1.5cmX1.9cm

    Extending the limits of wireless power transfer to miniaturized implantable electronic devices

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    Implantable electronic devices have been evolving at an astonishing pace, due to the development of fabrication techniques and consequent miniaturization, and a higher efficiency of sensors, actuators, processors and packaging. Implantable devices, with sensing, communication, actuation, and wireless power are of high demand, as they pave the way for new applications and therapies. Long-term and reliable powering of such devices has been a challenge since they were first introduced. This paper presents a review of representative state of the art implantable electronic devices, with wireless power capabilities, ranging from inductive coupling to ultrasounds. The different power transmission mechanisms are compared, to show that, without new methodologies, the power that can be safely transmitted to an implant is reaching its limit. Consequently, a new approach, capable of multiplying the available power inside a brain phantom for the same specific absorption rate (SAR) value, is proposed. In this paper, a setup was implemented to quadruple the power available in the implant, without breaking the SAR limits. A brain phantom was used for concept verification, with both simulation and measurement data.This work is supported by FCT with the reference project PTDC/EEI-TEL/5250/2014, by FEDER funds through Projecto 3599-Promover a Produção Científica e Desenvolvimento Tecnológico e a Constituição de Redes Temáticas (3599-PPCDT) and by grant SFRH/BD/116554/2016.info:eu-repo/semantics/publishedVersio

    Recent Advances on Implantable Wireless Sensor Networks

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    Implantable electronic devices are undergoing a miniaturization age, becoming more efficient and yet more powerful as well. Biomedical sensors are used to monitor a multitude of physiological parameters, such as glucose levels, blood pressure and neural activity. A group of sensors working together in the human body is the main component of a body area network, which is a wireless sensor network applied to the human body. In this chapter, applications of wireless biomedical sensors are presented, along with state-of-the-art communication and powering mechanisms of these devices. Furthermore, recent integration methods that allow the sensors to become smaller and more suitable for implantation are summarized. For individual sensors to become a body area network (BAN), they must form a network and work together. Issues that must be addressed when developing these networks are detailed and, finally, mobility methods for implanted sensors are presented

    Stepper microactuators driven by ultrasonic power transfer

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    Advances in miniature devices for biomedical applications are creating ever-increasing requirements for their continuous, long lasting, and reliable energy supply, particularly for implanted devices. As an alternative to bulky and cost inefficient batteries that require occasional recharging and replacement, energy harvesting and wireless power delivery are receiving increased attention. While the former is generally only suited for low-power diagnostic microdevices, the latter has greater potential to extend the functionality to include more energy demanding therapeutic actuation such as drug release, implant mechanical adjustment or microsurgery. This thesis presents a novel approach to delivering wireless power to remote medical microdevices with the aim of satisfying higher energy budgets required for therapeutic functions. The method is based on ultrasonic power delivery, the novelty being that actuation is powered by ultrasound directly rather than via piezoelectric conversion. The thesis describes a coupled mechanical system remotely excited by ultrasound and providing conversion of acoustic energy into motion of a MEMS mechanism using a receiving membrane coupled to a discrete oscillator. This motion is then converted into useful stepwise actuation through oblique mechanical impact. The problem of acoustic and mechanical impedance mismatch is addressed. Several analytical and numerical models of ultrasonic power delivery into the human body are developed. Major design challenges that have to be solved in order to obtain acceptable performance under specified operating conditions and with minimum wave reflections are discussed. A novel microfabrication process is described, and the resulting proof-of-concept devices are successfully characterized.Open Acces

    Silicon nanowire field-effect transistors for the detection of proteins

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    In this dissertation I present results on our efforts to increase the sensitivity and selectivity of silicon nanowire ion-sensitive field-effect transistors for the detection of biomarkers, as well as a novel method for wireless power transfer based on metamaterial rectennas for their potential use as implantable sensors. The sensing scheme is based on changes in the conductance of the semiconducting nanowires upon binding of charged entities to the surface, which induces a field-effect. Monitoring the differential conductance thus provides information of the selective binding of biological molecules of interest to previously covalently linked counterparts on the nanowire surface. In order to improve on the performance of the nanowire sensing, we devised and fabricated a nanowire Wheatstone bridge, which allows canceling out of signal drift due to thermal fluctuations and dynamics of fluid flow. We showed that balancing the bridge significantly improves the signal-to-noise ratio. Further, we demonstrated the sensing of novel melanoma biomarker TROY at clinically relevant concentrations and distinguished it from nonspecific binding by comparing the reaction kinetics. For increased sensitivity, an amplification method was employed using an enzyme which catalyzes a signal-generating reaction by changing the redox potential of a redox pair. In addition, we investigated the electric double layer, which forms around charges in an electrolytic solution. It causes electrostatic screening of the proteins of interest, which puts a fundamental limitation on the biomarker detection in solutions with high salt concentrations, such as blood. We solved the coupled Nernst-Planck and Poisson equations for the electrolyte under influence of an oscillating electric field and discovered oscillations of the counterion concentration at a characteristic frequency. In addition to exploring different methods for improved sensing capabilities, we studied an innovative method to supply power to implantable biosensors wirelessly, eliminating the need for batteries. A metamaterial split ring resonator is integrated with a rectifying circuit for efficient conversion of microwave radiation to direct electrical power. We studied the near-field behavior of this rectenna with respect to distance, polarization, power, and frequency. Using a 100 mW microwave power source, we demonstrated operating a simple silicon nanowire pH sensor with light indicator

    A History of Materials and Technologies Development

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    The purpose of the book is to provide the students with the text that presents an introductory knowledge about the development of materials and technologies and includes the most commonly available information on human development. The idea of the publication has been generated referring to the materials taken from the organic and non-organic evolution of nature. The suggested texts might be found a purposeful tool for the University students proceeding with studying engineering due to the fact that all subjects in this particular field more or less have to cover the history and development of the studied object. It is expected that studying different materials and technologies will help the students with a better understanding of driving forces, positive and negative consequences of technological development, etc

    The Papers of Thomas A. Edison

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    This richly illustrated volume explores Edison’s inventive and personal pursuits from 1885 to 1887.Two decades after the American Civil War, no name was more closely associated with the nation’s inventive and entrepreneurial spirit than that of Thomas Edison. The restless changes of those years were reflected in the life of America’s foremost inventor. Having cemented his reputation with his electric lighting system, Edison had decided to withdraw partially from that field. At the start of 1885, newly widowed at mid-life with three young children, he launched into a series of personal and professional migrations, setting in motion chains of events that would influence his work and fundamentally reshape his life. Edison’s inventive activities took off in new directions, flowing between practical projects (such as wireless and high-capacity telegraph systems) and futuristic ones (exploring forms of electromagnetic energy and the convertibility of one to another). Inside of two years, he would travel widely, marry the daughter of a prominent industrialist and religious educator, leave New York City for a grand home in a sylvan suburb, and construct a winter laboratory and second home in Florida. Edison’s family and interior life are remarkably visible at this moment; his papers include the only known diary in which he recorded personal thoughts and events. By 1887, the familiar rhythms of his life began to reassert themselves in his new settings; the family faded from view as he planned, built, and occupied a New Jersey laboratory complex befitting his status. The eighth volume of the series, New Beginnings includes 358 documents (chosen from among thousands) that are the most revealing and representative of Edison’s work, life, and place in American culture in these years. Illustrated with hundreds of Edison’s drawings, these documents are further illuminated by meticulous research on a wide range of sources, including the most recently digitized newspapers and journals of the day

    Social work with airports passengers

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    Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

    Muon (g-2) Technical Design Report

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    The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval

    Energy: A continuing bibliography with indexes, issue 13

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    This bibliography lists 1036 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1977 through March 31, 1977
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