Other Electrical and Computer Engineering Commons^™

Series Resonant Converters With Medium Voltage Sic Mosfets For Electric Aircraft Applications, Xinyuan Du

Graduate Theses and Dissertations

To develop high-performance high- power-density MV power converters, the emerging silicon carbide (SiC) devices are more attractive than their silicon (Si) counterparts, since the fast switch frequency brought by the SiC can effectively reduce the volume and weight of the filter components and thus increase the converter power density. From the converter topology perspective, with the MV dc distribution, the single stage isolated dc/dc converter are suitable for next-generation electric aircraft system due to soft switching and high power density. In this work, comprehensive static and dynamic characterizations were conducted for the latest 6.5 kV silicon carbide (SiC) MOSFETs from …

Design And Testing Of A Gallium Nitride Power Amplifier For High-Temperature Radar Applications, Walker Landry Harbison

Graduate Theses and Dissertations

This thesis offers the design, fabrication, and evaluation of a gallium nitride (GaN) power amplifier integrated circuit (IC) intended for high-temperature radar applications. Radar systems are used in many different applications, such as defense, aerospace, and weather. For their function, these systems require high power, efficiency, and reliability under a wide range of operating conditions. Taking advantage of the material properties of GaN, including its high breakdown voltage, wide bandgap, and thermal conductivity bolstered by the use of silicon carbide in the substrate, this work focuses on examining amplifier performance in both ambient and elevated temperature conditions. The PA was …

Construction And Characterization Of An Rf Anechoic Range, Logan Gentry

Electrical Engineering and Computer Science Undergraduate Honors Theses

Anechoic RF ranges are electromagnetically quiet spaces intended to provide conditions suitable for testing and classifying electronic equipment. Typically, ranges are constructed indoors, which presents a number of design challenges related to room geometry, cost, and material selection. This report describes the creation of an indoor anechoic range intended for characterization of antennas. Furthermore, the range is characterized for performance across a wide range of discrete frequencies in the UHF band according to CISPR standards, resulting in the determination of a lower frequency limit at which the room performance begins to degrade. The characterization of this range agrees with far-field …

Design Considerations Of A Gpu, Nicholas M. Devilliers

Electrical Engineering and Computer Science Undergraduate Honors Theses

With the current era of AI technology, the era of single instruction multiple data has become an increasingly viable solution to accelerate training. The problem is that while software to use GPUs and other hardware accelerators, designing GPUs and ASIC devices has become increasingly more expensive and there aren’t great examples of generic GPUs that anyone can use and modify. In this thesis, there are four design considerations that will be discussed and how they affect the result of a generic GPU. The four considerations that were talked about in the thesis are, word width, arithmetic type, number of stages, …

Enhancing Webtas: From An Atam Simulator To A Developmental Environment, Elizabeth G. Schmidt

Electrical Engineering and Computer Science Undergraduate Honors Theses

As interest in a niche research area, like the abstract Tile Assembly Model (aTAM), grows it is crucial to ensure that simulation tools are accessible and user-friendly for a broad audience. Existing resources can pose challenges for less experienced users, highlighting the need for enhancements that improve usability and functionality. To address these issues, key upgrades to the current online simulation platform, WebTAS, were implemented, including breakpoint functionality and nondeterminism checks, alongside features such as XML file integration, image capturing, and simulation view resets. These enhancements collectively elevate the platform from a basic learning tool to a comprehensive environment for …

Esd-Robust 4h-Sic Low-Voltage Cmos Technology Development For High Temperature, Hui Wang

Graduate Theses and Dissertations

This dissertation explores the development and optimization of electrostatic discharge (ESD)-robust, low-voltage CMOS technology using 4H-silicon carbide (SiC) tailored for high-temperature applications, addressing the critical need for reliable semiconductor devices in harsh environmental conditions. The advent of SiC as a semiconductor material offers significant advantages over traditional silicon (Si) in harsh environments, including higher thermal conductivity, greater electron mobility, and improved electrical characteristics at elevated temperatures. This research explores the integration of 4H-SiC into CMOS technology to enhance device reliability and performance in extreme conditions such as those found in aerospace, automotive, and energy sectors. The study begins with a …

The Wideband Tunability Of Double Gunn Diodes, Latarence Butts, Samir M. El-Ghazaly

Electrical Engineering Faculty Publications and Presentations

Gunn diodes use the Ridley–Watkins–Hilsum effect to generate low noise millimeter wave signals for communication and sensing applications. However, Monte Carlo calculations indicate that the velocity–field characteristics of compensated GaAs contain a second peak due to phonon scattering. A novel device that leverages this double Ridley–Watkins–Hilsum effect to achieve ultra-wideband tunability of low-noise millimeter waves is proposed in this article. The second region of negative differential mobility is gradually introduced in seven mobility profiles, which are each simulated in eight device lengths. It is found that a 2.5 μm Gunn diode with a compensation ratio of 0.6 operating at …

Experimental And Computational Analysis Of Broadband Thz Photoconductive Antennas, Zachary Uttley, Jose Santos Batista, Bilal Pirzada, Magda El-Shenawee

Electrical Engineering Faculty Publications and Presentations

The work presents the fabrication and measurements of four LT-GaAs photoconductive terahertz (THz) antennas with different geometries of metallic electrodes. The goal is to analyze the overall bandwidth of the antennas through a comparison between the spectra of the generated photocurrent in the antenna gap, the radiated electric field THz pulse, and the S₁₁ parameter of the metallic electrodes. The photocurrent density and the S₁₁ parameters are computed using COMSOL multiphysics, while the generated THz pulse was experimentally measured using a time-domain spectroscopy system. The polarizations of the photoconductive antennas are experimentally measured, using x-cut quartz crystal halfwave …

Effects Of Electrodes Layout On Performance Of Millimeter-Wave Transistors, Soheil Nouri, Samir M. El-Ghazaly

Electrical Engineering Faculty Publications and Presentations

This work presents a systematic parameter extraction methodology for modeling of millimeter-wave transistors. The physics-based parameter extraction approach in this study is included in the wave-electron-transport model to improve the accuracy of the simulation results. The effects of extrinsic parameters on the performance of the device are also analyzed in detail. Skin effects and sharp metallization edge effects as the two physical phenomena that impact the current distribution and the resistance of millimeter-wave transistors are studied thoroughly. Two common electrode layout variations, the T configuration and the fork configuration, are compared. The comparison mainly targeted their performance on upper millimeter …

Measuring The Electrical Properties Of 3d Printed Plastics In The W-Band, Noah Gregory

Electrical Engineering Undergraduate Honors Theses

3D printers are a method of additive manufacturing that consists of layering material to produce a 3D structure. There are many types of 3D printers as well as many types of materials that are capable of being printed with. The most cost-effective and well documented method of 3D printing is called Fused Deposition Modeling (FDM). FDM printers work by feeding a thin strand of plastic filament through a heated extruder nozzle. This plastic is then deposited on a flat, typically heated, surface called a print bed. The part is then built by depositing thin layers of plastic in the shape …

Signal Analysis Of Photovoltaic Systems For Multilevel Cybersecurity, Wesley G. Schwartz

Electrical Engineering Undergraduate Honors Theses

The cybersecurity of grid-connected power electronics is a rapidly developing field as more and more of these devices become a part of the Internet of Things. The objective of this thesis to analyze the current control signals of a photovoltaic (PV) inverter and develop an interface board for the implementation of a new cyber-secure controller.

In this thesis, the testing and in-depth analysis of the current PV inverter control system will be conducted. Using the data collected, an interface board will be developed to allow the use of the Unified Control Board (UCB), developed by Chris Farnell, in the PV …

Interdisciplinary Education Outreach With Traffic Sensor Build Kits, Sarah V. Hernandez, Mariah B. Crews

Civil Engineering Teaching and Learning

The goal of this project was to attract K-12 students to transportation engineering careers through STEM outreach programs. To accomplish this goal, the object of the project was to design and implement maritime freight oriented educational outreach activities centered on traffic sensing technologies for middle, high school, and first-year college students. In MarTREC Project 5011 (Evaluating the Performance of Intermodal Connectors), the research team designed a low-cost, easily implementable LiDAR and Bluetooth sensor bundle that was capable of detecting, characterizing, and tracking freight trucks as they traveled to and from inland waterway port areas. The sensor provided data necessary to …

Characterization Of High Temperature Optocoupler For Power Electronic Systems, David Gonzalez

Electrical Engineering Undergraduate Honors Theses

High-temperature devices have been rapidly increas due to the implementation of new technologies like silicon carbide, high-temperature ceramic, and others. Functionality under elevated temperatures can reduce signal integrity reducing the reliability of power electronic systems. This study presents an ongoing research effort to develop a high-temperature package for optocouplers to operate at higher temperature compared with commercial devices. Low temperature co-fired ceramic (LTCC) was used as the substrate. Bare die commercial LED and photodetectors were attached to the substrate and tested for functionality. Preliminary results show enhanced performance at elevated temperatures compared to a commercial optocoupler device.

Counterfeit Detection With Multispectral Imaging, Ian Spatz

Electrical Engineering Undergraduate Honors Theses

Multispectral imaging is becoming more practical for a variety of applications due to its ability to provide hyper specific information through a non-destructive analysis. Multispectral imaging cameras can detect light reflectance from different spectral bands of visible and nonvisible wavelengths. Based on the different amount of band reflectance, information can be deduced on the subject. Counterfeit detection applications of multispectral imaging will be decomposed and analyzed in this thesis. Relations between light reflectance and objects’ features will be addressed. The process of the analysis will be broken down to show how this information can be used to provide more insight …

Methods To Remotely Eliminate Biofilm From Medical Implants Using 2.4 Ghz Microwaves, Brett Glenn

Mechanical Engineering Undergraduate Honors Theses

Infections associated with biofilm growth are usually challenging to eradicate due to their high tolerance toward antibiotics [11, 12]. Biofilms often form on the inert surfaces of medically implanted devices [13]. No matter the sophistication, microbial infections can develop on all medical devices and tissue engineering constructs [12]. Related infections lead to 2 million cases annually in the U.S., costing the healthcare system over $5 billion in additional healthcare expenses [12].

Novel solutions to biofilm’s microbial colonization span the spectrum of engineering and science disciplines. Yet a practical solution still does not exist. The research presented here will explore a …

Command Validation For Cybersecure Power Router, Isaac M. Kroger

Electrical Engineering Undergraduate Honors Theses

For grid-connected homes equipped with solar panels, power electronics are necessary to manage and convert power between the solar panels, battery storage, grid, and residential load. A power router can be used to manage these power electronics and govern power generation, storage, and distribution within the household. This level of control makes power routers that do not employ cybersecurity a target for external attacks. The use of command validation is an effective way to prevent unauthorized commands from maliciously altering the state of a home’s power router. The purpose of this thesis is to describe the development of the command …

Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman

Graduate Theses and Dissertations

The goal of this work is to investigate terahertz technology for assessing the surgical margins of breast tumors through electromagnetic modeling and terahertz experiments. The measurements were conducted using a pulsed terahertz system that provides time and frequency domain signals. Three types of breast tissues were investigated in this work. The first was formalin-fixed, paraffin-embedded tissues from human infiltrating ductal and lobular carcinomas. The second was human tumors excised within 24-hours of lumpectomy or mastectomy surgeries. The third was xenograft and transgenic mice breast cancer tumors grown in a controlled laboratory environment to achieve more data for statistical analysis.

Experimental …

Introduction To Signal Timing & Traffic Control, Sarah V. Hernandez, Mariah Crew, Karla Diaz-Corro, Taslima Akter

Civil Engineering Teaching and Learning

The purpose of these lesson plans is to introduce students to traffic signalization basics. Students will be lead through a series of mini-lectures on traffic control and signalization including a discussion on the limitations and benefits of traffic signalization. The lesson plans compliment a computer simulation “game” in which students act as manual operators for a single up to four by four gridded intersection. Students attempt to control the progression of signals to understand the relationship between signal timing and user delay. Through experimentation with the simulation, students generate a presentation discussing the benefits and drawbacks of signal timing and …

Transportation Engineering: Traffic Control Simulator, Sarah V. Hernandez, Karla Diaz-Corro, Taslima Akter, Magdalena Asborno, Fu Durandal

Civil Engineering Teaching and Learning

The purpose of these lesson plans is to introduce students to traffic signalization basics. Students will be lead through a series of mini-lectures on traffic control and signalization including a discussion on the limitations and benefits of traffic signalization. The lesson plans compliment a computer simulation “game” in which students act as manual operators for a single up to four by four gridded intersection. Students attempt to control the progression of signals to understand the relationship between signal timing and user delay. Through experimentation with the simulation, students generate a presentation discussing the benefits and drawbacks of signal timing and …

Time Domain Analysis Of Terahertz Photoconductive Antennas Using High- Frequency Structure Simulator (Hfss), David Carballo

Electrical Engineering Undergraduate Honors Theses

In this thesis, an in-depth guide and description on how to model and perform frequency and mainly time domain analysis of a THz photoconductive antenna using HFSS will be presented. The main purpose of this thesis is to master and document the procedures for transient domain analysis in HFSS to fill the lack of documentation about this topic. Moreover, another goal is to compare the results from HFSS with the ones from another program, COMSOL (conducted by a PhD student), in order to validate the correctness of the procedure.

From this thesis, it can be concluded that in order to …

Achieving A Better Balance Between Productivity And Performance On Fpgas Through Heterogeneous Extensible Multiprocessor Systems, Abazar Sadeghian

Graduate Theses and Dissertations

Field Programmable Gate Arrays (FPGAs) were first introduced circa 1980, and they held the promise of delivering performance levels associated with customized circuits, but with productivity levels more closely associated with software development. Achieving both performance and productivity objectives has been a long standing challenge problem for the reconfigurable computing community and remains unsolved today. On one hand, Vendor supplied design flows have tended towards achieving the high levels of performance through gate level customization, but at the cost of very low productivity. On the other hand, FPGA densities are following Moore's law and and can now support complete multiprocessor …

Wireless Monitoring Of Driver's Pulse Rate And Temperature Using Hand Gloves Approach, Rohith Reddy Narala

Graduate Theses and Dissertations

There is growing concern about dangers correlated with driving, for people with known cardiovascular diseases. However, the association between having a chronic cardiovascular disease and being involved in a motor vehicle crash remains controversial. This study aims to monitor people with known medical emergencies or other medical conditions while driving [1]. It also helps the co-passengers to be cautious while the person is driving with an abnormal health condition. Designed it to be convenient and also can be easily adaptable by the end user.

The proposed project focuses on a wearable sensor glove that equipped with a pulse rate sensor, …

The Synthesis And Characterization Of Copper Indium Sulfide And Cadmium Selenide Nanocrystals And Their Applications In Photodetectors, Zachary T. Bever

Electrical Engineering Undergraduate Honors Theses

Semiconductor nanocrystals are a topic of much interest in electrical engineering. Their use has been explored for many applications. This paper investigates the synthesis and characterization of CuInS2 and CdSe nanocrystals. As the nanocrystals were left in reaction for increasing amounts of time, the bandgap of the material decreased as the nanocrystal size increased due to the quantum confinement effect. The CdSe nanocrystals were then investigated in a photodetector application which achieved a detectivity on the order of 10^9 cmHz^(1/2)W^(-1).

Development Of Spray Cooling For High Heat Flux Electronics, Jeremy Scott Junghans

Graduate Theses and Dissertations

The thermal demands of modern day electronic systems require innovative thermal solutions. Spray cooling has proven to be able to cool heat fluxes orders of magnitude higher than traditional cooling methodologies. This work includes a comparison of spray cooling to standard thermal management methodologies. Key system parameters and considerations are discussed. The properties of available packaging materials and their effect on the reliability of a spray cooled system are presented. Parameters such as fluid temperature, droplet size, fluid velocity and flow rate all directly impact performance and are detailed in this work. Finally, results from of a wide range of …

A Methodology For Implementing Rf Bists In Production Testing To Replace Rf Conventional Tests, Deepa Mannath

Graduate Theses and Dissertations

Production testing of Radio Frequency (RF) devices is challenging due to the complex nature of the tests that have to be performed to verify functionality. In this dissertation a methodology to replace the complex and expensive RF functional tests with defect-oriented Built-in Self Tests (BiSTs) is detailed. If a design has sufficient margin to RF specifications then RF tests can be replaced with structural tests using a new data analysis technique called quadrant analysis, which is presented. Data from the analysis of over one million production units of said System on Chip (SoC) is presented along with the results of …

Parameter Extraction Software For Silicon Carbide Schottky, Merged Pin Schottky And Pin Power Diode Models, Edgar Cilio

Inquiry: The University of Arkansas Undergraduate Research Journal

A software program for on-state parameter extraction is presented for the realization of a high quality model for SiC Schottky, Merged PiN Schottky, and PiN Power diodes based on McNutt and Mantooth's Comprehensive SiC Diode model [ 1 ].

Comparison Of High-Temperature Superconductors In Multi-Chip Module Applications, D. E. Ford, S. S. Scott, S. S. Ang, W. D. Brown

Journal of the Arkansas Academy of Science

In the application of high-temperature superconductors (HTSCs) in multi-chip module (MCM) technology, it is first necessary to investigate the advantages and disadvantages of the various HTSC compounds. The standard criteria for comparing the suitability of HTSCs in electronics applications has been critical temperature (Tc )and critical current density (Jc ). It is also necessary to consider the physical properties of HTSCs in relation to the various processing techniques required in fabrication of MCMs. These techniques can be grouped into four main areas: deposition, patterning, packaging, and characterization. The four main HTSC materials, Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O, Tl,Ba-Ca-Cu-O and Hg-Ba-Ca-Cu-O, will be compared …

Multiple Sample Cryostat For The Determination Of Superconductor Properties, G. Burnside, Roger M. Hawk, Paul C. Mcleod

Journal of the Arkansas Academy of Science

Cryostats which are currently used to characterize the properties of superconductors between 4 K and 100 K are primarily single sample devices. The purpose of this paper is to present an instrument design which can hold up to five (5) one cm. diameter samples at a stable temperature (+ /-0.1K) within the above range specified while measurements of the sample properties are made.

Sputter Deposition And Thallination Of Ti-Ba-Ca-Cu-O Superconducting Thin Films, T. H. Dhayagude, S. S. Ang, W. D. Brown

Journal of the Arkansas Academy of Science

Thallination techniques used for the fabrication of sputter-deposited TI2Ba2CaCu 2Ox and TI2Ba2Ca2Cu3Ox superconducting thin films were investigated. Differences in elemental composition of precursor Ba-Ca-Cu-O sputtering targets were found to yield different superconducting phases. Thallination conditions which yielded transition temperatures as high as 122 K for samples annealed in air are described. Finally, reactive ion etching of films using a mixture of chlorine and argon gases is discussed.

Data Acquisition And Control Program For Chromatography, M. Keith Hudson, William G. Hood

Journal of the Arkansas Academy of Science

No abstract provided.