Engineering Commons^™

Design, Fabrication And Characterization Of Zero Power Sensor/Harvester For Smart Grid Applications, Zeynel Guler

Mechanical Engineering ETDs

This study presents a flexible sensor/harvester device to be used in both electromagnetic sensing and energy harvesting applications for smart grids. When a current passes through a wire, the sensor detects the magnetic field created by that current. The sensor magnet interacts with the wire magnetic field resulting in a transfer of energy through the piezoelectric cantilever. Piezoelectric, conductive, magnetic, and magnetostrictive composite thin films were prepared to fabricate this device.

Initially, the magnet of the cantilever was optimized considering its shape, thickness, length, taper angle etc. via both simulations and experiments. Peak to peak voltage versus cantilever position graph …

Piezoelectric And Conductive Polymer Based Flexible Devices Enabling Cardiovascular Health Sensing And Energy Harvesting, Andrew Closson

Dartmouth College Ph.D Dissertations

Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible …

Synthesis And Characterization Of Vo2 Thin Films On Piezoelectric Substrates, Samee Azad

All Theses

Polycrystalline VO₂ thin films synthesized on two piezoelectric substrates (AT-cut quartz and GaN/AlGaN/GaN/Si) using low pressure direct oxidation technique have been characterized and compared to VO₂ grown on traditional non-piezoelectric substrates sapphire and SiO₂/Si. X-ray diffraction and atomic force microscopy characterization performed on the as grown films confirmed high quality of the VO₂ films grown on both the piezoelectric and non-piezoelectric substrates. Changes in material properties associated with the semiconductor metal transition (SMT) of the VO₂ films were investigated through resistivity and transmitted optical power changes measured across the SMT. It was observed that …

Material Characterization And Comparison Of Sol-Gel Deposited And Rf Magnetron Deposited Lead Zirconate Titanate Thin Films, Katherine Lynne Miles

Mechanical Engineering ETDs

Lead zirconate titanate (PZT) has been a material of interest for sensor, actuator, and transducer applications in microelectromechanical systems (MEMS). This is due to their favorable piezoelectric, pyroelectric and ferroelectric properties. While various methods are available to deposit PZT thin films, radio frequency (RF) magnetron sputtering was selected to provide high quality PZT films with the added capability of batch processing. These sputter deposited PZT films were characterized to determine their internal film stress, Young’s modulus, composition, and structure. After characterization, the sputtered PZT samples were poled using corona poling and direct poling methods. As a means of comparison, commercially …

Modelling And Evaluation Of Piezoelectric Actuators For Wearable Neck Rehabilitation Devices, Shaemus D. Tracey

Electronic Thesis and Dissertation Repository

Neck pain is the most common neck musculoskeletal disorder, and the fourth leading cause of healthy years lost due to disability in the world. Due to the need of hands-on physical therapy and Canada’s aging population, access to treatment will become highly constrained. Wearable devices that allow at-home rehabilitation address this future limitation. However, few have emerged from the laboratory setting because they are limited by the use of conventional actuators. An overlooked type of actuation technology is that of piezoelectric actuators, more specifically, travelling wave ultrasonic motors (TWUM).

In this work, a clear procedure that outlines how the required …

Zero-Power Ac Current Sensor, Omar Aragonez

Mechanical Engineering ETDs

In this study, a magnetic piezoelectric cantilever powered AC current and frequency sensor is proposed. This paper covers the configuration of the experimental setup, finite element modeling of the magnetic coupling, and the optimal spatial location of the magnetic proof mass in relation to the wire for smart grid applications. Solid and stranded copper wires of various gauges were used and carried current up to 30A. The magnets act as a proof mass to lower the frequency while also coupling to the magnetic field generated by the current carrying wire. The frequency of the AC current produces a sinusoidal force …

Design And Characterization Of Piezoelectric Actuator On Flexible Substrate For Conductive Hearing Aids, Sandhya Chapagain

Graduate Research Theses & Dissertations

Conductive hearing loss (CHL) is a common condition among infants and young children. CHL caused by an obstruction/damage in the auditory canal, preventing sounds from properly transferring into the inner ear. Failure in timely treatment in the early stage of life will delay brain and physical development, affecting language acquisition, learning abilities, communication, and social skills. The available treatment for CHL is corrective surgeries and conductive hearing aids. These options are invasive and are not suitable for newborns, infants, and pediatric patients with fragile organs. Here, we designed and characterized micro-actuators on flexible substrates to generate vibrations on the surface …

Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin

Honors Theses

Structural health monitoring has the potential to allow composite structures to be more reliable and safer, then by using more traditional damage assessment techniques. Structural health monitoring (SHM) utilizes individual sensor units that are placed throughout the load bearing sections of a structure and gather data that is used for stress analysis and damage detection. Statistical time based algorithms are used to analyze collected data and determine both damage size and probable location from within the structure. While traditional calculations and life span analysis can be done for structures made of isotropic materials such as steel or other metals, composites …

Ultra-Thin Aluminum Nitride Thin Films For Flexible Mems Sensors, Md Sajeeb Rayhan

Electrical Engineering Dissertations

Microelectromechanical systems (MEMS) sensors using ultrathin aluminum nitride (AlN) film were developed and fabricated using conventional photolithography techniques in the class 100 clean room with a view to integrate them in flexible substrates along with flexible electronics. The MEMS sensors were designed, analytically modeled, fabricated and characterized. Some of the MEMS sensors were only designed and simulated using finite element method (FEM) for the scope of the dissertation. These MEMS sensors can be applied to many applications such as automobile, robotics, biomedical, biometrics, health condition monitoring, GPS tracking devices, smartphones and aircrafts. MEMS pressure sensors using AlN based piezoelectric film …

Faraday Rechargeable Battery System, Alex Gasper, Bret Omsberg

Electrical Engineering

The modern electronic age has given birth to a variety of innovative and hand-held devices that are carried with the consumer nearly 24 hours a day, seven days a week. The one shortfall of these devices is their energy storage, or in most cases, a battery. The Faraday Rechargeable Battery System is a unique system that will generate electricity through rotational movement of a tire. This can be a bike, a car, or any other transportation vehicle that uses wheels for movement. The kinetic energy that is engendered either by the user or an engine can then be converted into …

Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi

Electronic Theses and Dissertations

The main focus of this dissertation is to characterize and improve the performance of thin-film piezoelectric-on-substrate (TPoS) lateral-mode resonators and filters. TPoS is a class of piezoelectric MEMS devices which benefits from the high coupling coefficient of the piezoelectric transduction mechanism while taking advantage of superior acoustic properties of a substrate. The use of lateral-mode TPoS designs allows for fabrication of dispersed-frequency filters on a single substrate, thus significantly reducing the size and manufacturing cost of devices. TPoS filters also offer a lower temperature coefficient of frequency, and better power handling capability compared to rival technologies all in a very …

Rf Mems Resonators For Mass Sensing Applications, Ivan Fernando Rivera

USF Tampa Graduate Theses and Dissertations

Sensing devices developed upon resonant microelectromechanical and nanoelectromechanical (M/NEMS) system technology have become one of the most attractive areas of research over the past decade. These devices make exceptional sensing platforms because of their miniscule dimensions and resonant modes of operation, which are found to be extremely sensitive to added mass. Along their unique sensing attributes, they also offer foundry compatible microfabrication processes, low DC power consumption, and CMOS integration compatibility. In this work, electrostatically and piezoelectrically actuated RF MEMS bulk resonators have been investigated for mass sensing applications. The capacitively-transduced resonators employed electrostatic actuation to achieve desired resonance mode …

Development Of Electroplated-Ni Structured Micromechanical Resonators For Rf Application, Mian Wei

USF Tampa Graduate Theses and Dissertations

On-chip vibrating MEMS resonators with high frequency-Q product on par with that of the off-chip quartz crystals have attracted lots of attention from both academia and industry for applications on sensing, signal processing, and wireless communication. Up to now, several approaches for monolithic integration of MEMS and transistors have been demonstrated. Vibrating micromechanical disk resonators which utilize electroplated nickel as the structural material along with either a solid-gap high-k dielectric capacitive transducer or a piezoelectric transducer have great potential to offer unprecedented performance and capability of seamless integration with integrated circuits.

Despite the frequency drift problems encountered in early attempts …

Piezoelectric Powered Led Street Reflector, Collin Shane Douglass

Electrical Engineering

In many areas of Washington, it rains for a majority of the year. During rainy weather it becomes difficult to see street lanes and dividers, causing hazardous road conditions. The Piezoelectric Powered LED Street Reflector solves this problem. The PPL Street Reflector modifies a street reflector with LED lights. These lights help drivers clearly see where dividers and street lines are in non-ideal weather conditions, such as rain, fog, and snow. The PPL Street Reflector capabilities include harvesting energy through the Piezoelectric Effect, creating a self-sustaining device with minimal maintenance.

Piezoelectric-Based, Self-Sustaining Artificial Cochlea, Jared Evans

Browse all Theses and Dissertations

Hearing loss is a prevalent issue, affecting all ages in innumerable occupations. Cochlear implants are one solution to sensorineural hearing complications; and though they are commonly used, the electronic devices have limitations in power consumption and external equipment. Piezoelectric films emulate the relationship between the basilar membrane and inner hair cell structures of the human cochlear epithelium, inducing a potential difference in response to sound pressure. Through proper MEMS fabrication and material selection, an artificial cochlear can be developed utilizing piezoelectrics, which is self-sustainable and functions naturally with the mechanisms of the human ear. This research investigates the feasibility of …

Low Loss Vhf And Uhf Filters For Wireless Communications Based On Piezoelectrically-Transduced Micromechanical Resonators, Julio Mario Dewdney

USF Tampa Graduate Theses and Dissertations

For the past decade, a great deal of research has been focused towards developing a viable on-chip solution to replace the current state-of-the-art VHF and UHF filters based on SAW and FBAR technologies. Although filters based on SAW and FBAR devices are capable of fulfilling the basic requirements needed for IF and RF bandpass filtering and reference signal generation, an alternative solution that can enable the next generation of multi-frequency and multi-mode transceivers while enabling size and price reduction by allowing the manufacturing of single-chip monolithic RF transceivers is highly desired. In response to these new needs, piezoelectrically-transduced micromechanical filters …

Design And Analysis Of A Wind Energy Harvesting Circuit Using Piezoelectric Polymers, Jameson J. Thornton

Master's Theses

This thesis investigates a relatively new method for harvesting wind energy by using flexible piezoelectric polymers with additional sails to increase their ability to harvest wind energy. This paper also introduces a new topology deemed the “stacked buck” that allows for multiple inputs to a system with a single output. Derivations and analysis detail the workings of the “stacked buck” with a laboratory test to show a working model. This paper also reports another experiment done in a wind tunnel to analyze the capability of the piezoelectric polymers as sources to the “stacked buck” topology with measurements of the power …

Energy Band Engineering Using Polarization Induced Interface Charges In Mocvd Grown Iii-Nitride Heterojunction Devices, Neeraj Tripathi

Legacy Theses & Dissertations (2009 - 2024)

Characteristics of III-nitride based heterojunction devices are greatly influenced by the presence of high density of polarization induced interface charges. Research undertaken in the current doctoral thesis demonstrates the effect of presence of one, three and six sheets of polarization induced charges in three different III-nitride based devices, namely in a photocathode, a high electron mobility transistor (HEMT) and a hyperspectral detector structure. Through a systematic set of experiments and theoretical modeling an in-depth study of the interaction between multiple sheets of polarization induced charges and their impact on energy band profile was undertaken. Various device designs were studied and …

Two-Dimensional Microscanners With T-Shaped Hinges And Piezoelectric Actuators, Wenyu Song

LSU Master's Theses

For a wide range of application areas such as medical instruments, defense, communication networks, industrial equipment, and consumer electronics, microscanners have been a vibrant research topic. Among various fabrication methodologies, MEMS (microelectromechanical system) stands out for its small size and fast response characteristics. In this thesis, piezoelectric actuation mechanism is selected because of its low voltage and low current properties compared with other mechanisms, which are especially important for the target application of biomedical imaging. Although 1- and 2-dimensional microscanners with piezoelectric actuators have been studied by several other groups, this thesis introduces innovative improvements in design of the piezoelectric …