Radio frequency energy harvesting for autonomous systems

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyRadio Frequency Energy Harvesting (RFEH) is a technology which enables wireless power delivery to multiple devices from a single energy source. The main components of this technology are the antenna and the rectifying circuitry that converts the RF signal into DC power. The devices which are using Radio Frequency (RF) power may be integrated into Wireless Sensor Networks (WSN), Radio Frequency Identification (RFID), biomedical implants, Internet of Things (IoT), Unmanned Aerial Vehicles (UAVs), smart meters, telemetry systems and may even be used to charge mobile phones. Aside from autonomous systems such as WSNs and RFID, the multi-billion portable electronics market – from GSM phones to MP3 players – would be an attractive application for RF energy harvesting if the power requirements are met. To investigate the potential for ambient RFEH, several RF site surveys were conducted around London. Using the results from these surveys, various harvesters were designed and tested for different frequency bands from the RF sources with the highest power density within the Medium Wave (MW), ultra- and super-high (UHF and SHF) frequency spectrum. Prototypes were fabricated and tested for each of the bands and proved that a large urban area around Brookmans park radio centre is suitable location for harvesting ambient RF energy. Although the RFEH offers very good efficiency performance, if a single antenna is considered, the maximum power delivered is generally not enough to power all the elements of an autonomous system. In this thesis we present techniques for optimising the power efficiency of the RFEH device under demanding conditions such as ultra-low power densities, arbitrary polarisation and diverse load impedances. Subsequently, an energy harvesting ferrite rod rectenna is designed to power up a wireless sensor and its transmitter, generating dedicated Medium Wave (MW) signals in an indoor environment. Harvested power management, application scenarios and practical results are also presented

Electromagnetic Interference and Compatibility

Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method

Silicon - polymer hybrid integrated microwave photonic devices for optical interconnects and electromagnetic wave detection

textThe accelerating increase in information traffic demands the expansion of optical access network systems that require high-performance optical and photonic components. In short-range communication links, optical interconnects have been widely accepted as a viable approach to solve the problems that copper based electrical interconnects have encountered in keeping up with the surge in the data rate demand over the last decades. Low cost, ease of fabrication, and integration capabilities of low optical-loss polymers make them attractive for integrated photonic applications to support futuristic data communication networks. In addition to passive wave-guiding components, electro-optic (EO) polymers consisting of a polymeric matrix doped with organic nonlinear chromophores have enabled wide-RF-bandwidth and low-power active photonic devices. Beside board level passive and active optical components, on-chip micro- or nano-photonic devices have been made possible by the hybrid integration of EO polymers onto the silicon platform. In recent years, silicon photonics have attracted a significant amount of attentions, because it offers compact device size and the potential of complementary metal–oxide–semiconductor (CMOS) compatible photonic integrated circuits. The combination of silicon photonics and EO polymers can enable miniaturized and high-performance hybrid integrated photonic devices, such as electro-optic modulators, optical interconnects, and microwave photonic sensors. Silicon photonic crystal waveguides (PCWs) exhibit slow-light effects which are beneficial for device miniaturization. Especially, EO polymer filled silicon slotted PCWs further reduce the device size and enhance the device performance by combining the best of these two systems. The potential applications of these silicon-polymer hybrid integrated devices include not only optical interconnects, but also optical sensing and microwave photonics. In this dissertation, the design, fabrication, and characterization of several types of silicon-polymer hybrid photonic devices will be presented, including EO polymer filled silicon PCW modulators for on-chip optical interconnects, antenna-coupled optical modulators for electromagnetic wave detections, and low-loss strip-to-slot PCW mode converters. In addition, some polymer-based devices and silicon-based photonic devices will also be presented, such as traveling wave electro-optic polymer modulators based on domain-inversion directional couplers, and silicon thermo-optic switches based on coupled photonic crystal microcavities. Furthermore, some microwave (or RF) components such as integrated broadband bowtie antennas for microwave photonic applications will be covered. Some on-going work or suggested future work will also be introduced, including in-device pyroelectric poling for EO polymer filled silicon slot PCWs, millimeter- or Terahertz-wave sensors based on EO polymer filled plasmonic slot waveguide, low-loss silicon-polymer hybrid slot photonic crystal waveguides fabricated by CMOS foundry, logic devices based on EO polymer microring resonators, and so on.Electrical and Computer Engineerin

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators

Research and Technology 1995

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for fiscal year 1995. It comprises over 150 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: aeronautics, aerospace technology, space flight systems, engineering support, Lewis Research Academy, and technology transfer. A table of contents, an author index, and a list of NASA Headquarters program offices have been included to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors (for abstracts of these Lewis-authored reports, visit the Lewis Technical Report Server (LETRS) on the World Wide Web-http://letrs.lerc.nasa.gov/LeTRS/). In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information about Lewis' research, visit us on the World Wide web-http://www.lerc.nasa.gov

ESSE 2017. Proceedings of the International Conference on Environmental Science and Sustainable Energy

Environmental science is an interdisciplinary academic field that integrates physical-, biological-, and information sciences to study and solve environmental problems. ESSE - The International Conference on Environmental Science and Sustainable Energy provides a platform for experts, professionals, and researchers to share updated information and stimulate the communication with each other. In 2017 it was held in Suzhou, China June 23-25, 2017

Intelligent Circuits and Systems

ICICS-2020 is the third conference initiated by the School of Electronics and Electrical Engineering at Lovely Professional University that explored recent innovations of researchers working for the development of smart and green technologies in the fields of Energy, Electronics, Communications, Computers, and Control. ICICS provides innovators to identify new opportunities for the social and economic benefits of society.　 This conference bridges the gap between academics and R&D institutions, social visionaries, and experts from all strata of society to present their ongoing research activities and foster research relations between them. It provides opportunities for the exchange of new ideas, applications, and experiences in the field of smart technologies and finding global partners for future collaboration. The ICICS-2020 was conducted in two broad categories, Intelligent Circuits & Intelligent Systems and Emerging Technologies in Electrical Engineering