Terahertz materials for energy harvesting rectenna

2016 ◽  
Author(s):  
◽  
Zachary Thacker
Keyword(s):  
Energy Harvesting ◽  
Material Properties ◽  
Electromagnetic Waves ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
University Of Missouri ◽  
Nikola Tesla ◽  
Heinrich Hertz ◽  
Quantitative Results ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Energy collecting antenna have been studied for over a century. Early work performed by Heinrich Hertz and Nikola Tesla focused primarily on the transfer of energy at low frequency electromagnetic waves. The present work studies the possibility for harvesting electromagnetic energy present on earth from both terrestrial and solar sources. In general the energy density available increases with frequency, peaking around the visible portion of the spectrum. Because of the difficulty of converting high frequency signals, the present focus will be on the intermediate Terahertz range where the power density begins to increase. The goal of this work is to support the viability of an energy harvesting rectenna to collect and convert Terahertz frequency electromagnetic energy. The collection of the energy by an antenna is supported through probing frequency dependent material properties required for designing the device. Modelling of materials sensitive to THz waves is confirmed through spectroscopic measurements of fabricated devices. Device design is further supported by showing the relationship between the measured material properties and conversion, or rectification, efficiency. Finally, the concept is proved through quantitative results of THz rectenna measurements.

Academic libraries national conference program evaluation : meeting learner needs in a changing profession

2018 ◽  
Author(s):  
◽  
Julia Katherine Hart
Keyword(s):  
Learning Style ◽  
Academic Libraries ◽  
Comprehensive Evaluation ◽  
Survey Design ◽  
Academic Librarians ◽  
University Of Missouri ◽  
National Conference ◽  
Conference Organization ◽  
Quantitative Results ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The Academic Libraries National conference is a professional development opportunity for academic librarians. This study analyzed differences in preferred learning style of conference attendees based on years of library experience and the ability of the conference to meet the stated mission. Quantitative results indicated insignificant differences between preferred learning style and years of library experience. Qualitative results revealed support for meeting two of three mission components. Recommendations support modifications in practice for conference organization at the overarching, survey design, and future areas of study. These recommendations support efforts to create comprehensive evaluation of the conference.

A Belleville-Spring Based Piezoelectric or Electromagnetic Energy Harvester

2014 ◽  
Author(s):  
Davide Castagnetti
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Experimental Validation ◽  
Energy Harvester ◽  
Elastic System ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
Frequency Range ◽  
Modal Response ◽  
Force Displacement

Energy harvesting from kinetic ambient energy requires converters able to efficiently operate in the low frequency range. A limit of the solutions proposed in the literature, both electromagnetic and piezoelectric, is their operating frequency, which generally ranges from about 50 to 300 Hz. To overcome these limitations, this work proposes an innovative energy harvester exploiting two counteracting Belleville springs. Thanks to the peculiar height to thickness ratio of the springs a highly compliant elastic system is obtained, which can be used either for electromagnetic or piezoelectric harvesting. The harvester is modelled analytically and numerically both with regard to the force-displacement and to the modal response. The experimental validation of the harvester, highlights a noticeable power output but at a higher eigenfrequency than expected.

scholarly journals Electromagnetic Waves in Variable Media

2012 ◽  
Vol 67 (3-4) ◽  
pp. 111-131
Author(s):  
Ulrich Brosa
Keyword(s):  
Material Properties ◽  
Electromagnetic Waves ◽  
Maxwell's Equations ◽  
Constitutive Relations ◽  
Electromagnetic Energy ◽  
General Solutions ◽  
Optical Instruments ◽  
Dielectric Mirrors ◽  
New Foundations ◽  
Invisibility Cloaks

Two methods are explained to exactly solve Maxwell’s equations where permittivity, permeability, and conductivity may vary in space. In the constitutive relations, retardation is regarded. If the material properties depend but on one coordinate, general solutions are derived. If the properties depend on two coordinates, geometrically restricted solutions are obtained. Applications to graded reflectors, especially to dielectric mirrors, to filters, polarizers, and to waveguides, plain and cylindrical, are indicated. New foundations for the design of optical instruments, which are centered around an axis, and for the design of invisibility cloaks, plain and spherical, are proposed. The variability of material properties makes possible effects which cannot happen in constant media, e.g. stopping the flux of electromagnetic energy without loss. As a consequence, spherical devices can be constructed which bind electromagnetic waves

Wearable energy-harvesting micro devices

2016 ◽  
Author(s):  
◽  
Quang Thanh Nhat Nguyen
Keyword(s):  
Energy Harvesting ◽  
Low Cost ◽  
Transparent Electrode ◽  
Primary Energy ◽  
Silver Nanowire ◽  
University Of Missouri ◽  
Contact Electrification ◽  
Piezoelectric Effects ◽  
Continuous Power ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The focus of this dissertation is wearable energy-harvesting mircro devices. They are designed to harvest energy from the surrounding environment to supply power on the go for small electronic devices and sensors. We used low-cost and scalable fabrication methods that make them appropriate for mass production processes. There are four devices presented in this manuscript: the paper based ZnO nanogenerator using contact electrification and piezoelectric effects, the Teflon coated thread-shaped contact electrification fiber, the thread-shaped ZnO nanorod piezoelectric body sensor, and the silver nanowire transparent electrode for ZnO/TiO2 core-shell nanoparticle dye-sensitized solar cell. The demand of wearable electronic sensors for health monitoring has been increasing in recent years. However, the primary energy sources for these devices are still batteries that need to be replaced or recharged frequently. These batteries are also bulky and not easily incorporated into a garment. The devices presented in this manuscript are our efforts to address the problem of providing continuous power for wearable devices.

scholarly journals Investigation of biocompatible Parylene as triboelectric layer for wearable energy harvesting

2021 ◽  
Vol 7 (2) ◽  
pp. 771-774
Author(s):  
Franz Selbmann ◽  
Mario Baum ◽  
Marco Bobinger ◽  
Markus Gottwald ◽  
Maik Wiemer ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Material Properties ◽  
Dielectric Material ◽  
Low Frequency ◽  
Electrical Energy ◽  
Body Movements ◽  
Mechanical Motion ◽  
Energy Harvesters ◽  
Triboelectric Nanogenerators ◽  
High Output

Abstract Triboelectric nanogenerators (TENGs) are energy converters or energy harvesters that convert mechanical motion into electrical energy on the basis of their material properties. A particular advantage of the TENG is its ability to convert small, low-frequency and random mechanical movements that are relevant for body movements and wearable applications. Within the presented study, different Parylene types were analysed as the dielectric material in TENG and found to be promising with respect to providing high output voltages and powers, respectively. Besides the verification of the usability of Parylene for TENG and its superior triboelectric properties, also significant differences were found between the Parylene types.

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