Electrical and Computer Engineering Commons^™

A Direction Finding System Using Log Periodic Dipole Antennas In A Sparsely Sampled Linear Array, Jonathan Andrew Weldon

Browse all Theses and Dissertations

This thesis explores the use of wide band log periodic dipole array (LPDA) antennas in direction finding systems. A wide band log periodic antenna will be constructed and tested to ensure hardware capability. A novel approach utilizing non-uniform spacing in a linear array will be used to improve the spatial resolution of the direction finding system. These specialized linear arrays are known as minimum redundancy or non-redundant linear arrays.

A Structured Asic Approach To A Radiation Hardened By Design Digital Single Sideband Modulator For Digital Radio Frequency Memories, Thomas B. Pemberton

Browse all Theses and Dissertations

Digital Radio Frequency Memories (DRFM) are widely used as modules in digital signal processing. These modules can provide several forms of signal manipulation and storage capabilities. With single event effects caused by environmental radiation the need for a radiation hardened DRFM is increased. Typical radiation hardening involves the use of specialized foundries utilizing proprietary CMOS libraries that are expensive to build or adding lead packages around a chip that is expensive and add weight to the chip. An alternative radiation hardening technique is to utilize a radiation hardened by design library. This library includes digital gates that have been hardened …

Frequency Domain Processing Based Chaos Communication For Cognitive Radio, Daniel Y. Sundersingh

Browse all Theses and Dissertations

Chaotic systems are deterministic non-linear dynamical systems which have intrinsic properties such as: irregularity, aperiodicity, and are impossible to predict over long periods of time. Cognitive radio on the other hand, has emerged recently as a powerful means to tackle the spectrum congestion problem. The goal of this thesis is to combine the benefits of the chaos communication system with the cognitive radio to create a robust, highly secure, flexible chaotic cognitive radio system. We first begin with a short survey of chaotic communication and cognitive radio technology. Then we compare chaotic waveforms to other conventional PN sequences and show …

Wideband, High Data Rate Ku-Band Modulator Driver Amplifier For High Reliability Spaceborne Applications, Jeremy D. Gassmann

Browse all Theses and Dissertations

The increased demand for high resolution satellite imagery for government, military, and commercial applications is driving the need for high data rate, millimeter-wave transmission systems to relay imagery information to a ground-based end user. An important aspect of this system which interfaces digital information to the RF domain is the modulator driver. The current trend in miniaturization of electronics leaves systems more vulnerable to single-event radiation effects in spaceborne applications. In an effort to overcome this deficiency, a wideband, high data rate modulator driver circuit has been designed, built, and tested using only high reliability space rated electronic components. To …

An Automated Approach To A 90-Nm Cmos Drfm Dssm Circuit Design, Thomas A. Hopkins

Browse all Theses and Dissertations

A digital single sideband modulator (DSSM) for a digital radio frequency memory (DRFM) was designed and implemented in a commercial 90-nm radiation-hardened-by-design (RHBD) structured ASIC by Thomas Pemberton in cite{Pemberton}. This thesis synthesized the same DSSM structure in a non-hardened 90-nm commercial process and compared the synthesis results of the two for power, delay, and area. The number of I/O bits and taps in cite{Pemberton} and this thesis were purposely made high to create a large target for radiation testing. As should be expected, the RHBD DSSM reported greater power and area. However, the RHBD power models were only estimates. …

Adaptive Thresholding For Detection Of Radar Receiver Signals, Stephen R. Benson

Browse all Theses and Dissertations

Digital microwave receivers play a critical role in many of today's modern radar tracking systems. The need for these digital receivers to push the boundaries in terms of bandwidth and input dynamic ranges (DR) is vital for their use in radar signal tracking. Significant research has been conducted in the area of the fast Fourier transform (FFT) to aid in continuing to enhance the performance capabilities of digital microwave receivers. However, with the advancement and increased complexity of these systems, the need for an efficient and effective adaptive thresholding technique is becoming ever more present.

The proposed adaptive thresholding technique …

Hyperspectral Methods Of Determining Grit Application Density On Sandpaper, Lee A. Clark

Browse all Theses and Dissertations

A low cost real time method of determining the density of grit applied to sandpaper does not currently exist. This thesis will explore three methods for determining grit density from digital image data. A means to characterize the application in terms of frequency by using direct cosine transform basis images will be explored. An RX detector algorithm to characterize the image background will be tested. A linear unmixing methodology will be developed that characterizes the proportion of glue and grit present in each hyperspectral pixel vector.

Sulfur-Tolerant Catalyst For The Solid Oxide Fuel Cell, Bozeman Joe Frank Iii

Browse all Theses and Dissertations

JP-8 fuel is easily accessible, transportable, and has hydrogen content essential to solid oxide fuel cell (SOFC) operation. However, this syngas has sulfur content which results in a poisonous hydrogen sulfide that degrades electrochemical activity and causes complete SOFC failure in some cases. The goal is to synthesize and verify a cost-effective, catalyst supported on cerium oxide that either stabilizes ionic conductivity in the presence of hydrogen sulfide and/or is highly sulfur-resistant. After thorough computational analysis, it was concluded that the platinum-copper skin catalyst was the most cost-effective, sulfur-resistant catalyst. Experimental synthesis of copper, platinum, and platinum-copper skin catalysts supported …

Fault Diagnosis Of Vehicular Electric Power Generation And Storage, Hithesh Sanjiva Uliyar

Browse all Theses and Dissertations

Automotive vehicles are becoming increasingly dependent on electric power, and this trend will accelerate. The health of the vehicular electric power generation and storage (EPGS) system is crucial to enhance vehicle safety, fuel economy, and customer satisfaction.

In this research, a state-of-health (SOH) monitoring method is developed for automotive EPGS system, focusing on alternator related faults. Parity relations, characterizing the correlation among EPGS system signals under normal operating conditions, are generated using principal/minor component analysis techniques. Based on a design of structured residuals, the faults under consideration, including shorted diodes, belt slippage, and regulator fault, are successfully detected and isolated. …

Design Of Ultra High Speed Flash Adc, Low Power Folding And Interpolating Adc In Cmos 90nm Technology, Vinayashree Hiremath

Browse all Theses and Dissertations

In recent years, signal processing has gained ample significance making high speed and low voltage analog-to-digital converters (ADC) inevitable in numerous applications. Two such ADCs designed in CMOS 90nm technology are presented in this thesis.

In flash ADC, thermometer to binary encoder often becomes bottleneck in achieving high speed. An encoder deploying new CMOS logic, with fewer transistors through the use of pseudo-dynamic circuits is described. This 4 bit flash ADC operates at 5GHz with an average power dissipation of 1.3mW.

Folding and interpolation significantly reduces the number of comparators used in flash architecture. A 6 bit 400MSPS low power …

Multi-User Signal Classification Via Cyclic Spectral Analysis, Brent Edward Guenther

Browse all Theses and Dissertations

This research develops and evaluates several different methods for multi-user signal classification via cyclic spectral analysis. The first method uses the spectral correlation function (SCF) through temporal smoothing with the use of higher order cyclic statistics (HOCS) to allow for modulation classification. The second method uses the cyclic temporal cumulant function (CTCF) and the spectral coherence function (SOF) through frequency smoothing. Using a feature-based pattern recognition technique with the SOF can not only determine the number of signals present in the received signal, but can also give signal parameter estimation and group classification performance. The last method conducts further modulation …

Design Of Hf Forward Transformer Including Harmonic Eddy Current Losses, Dhivya Ammanambakkam Nagarajan

Browse all Theses and Dissertations

Pulse Width Modulated (PWM) Forward DC-DC converter is a buck-derived isolated power converter which is used extensively in low power to medium power applications. Satisfactory operation of the transformer utilized in forward converter plays a crucial role in the overall operation of the forward converter. Hence detailed analysis pertaining to design of forward transformer is important. The forward transformer is unique as the magnetizing inductance is not required to store magnetic energy. Additionally, the forward transformer has a tertiary winding, which is required to reset the core and to prevent core saturation. This adds to the complexity of design and …

Characterization Of An Inductively Coupled Plasma Produced In Argon At 13.56 Mhz., Lim Ai Nuan

Student Works (2010-2019)

The electrical and plasma characteristics of radio frequency (13.56 MHz) inductively coupled argon plasma (RF ICP) were studied in this project. On the electrical breakdown properties, the breakdown voltage has a general appearance of Paschen’s curve and the minimum is achieved at 0.1 mbar. After ignition, two modes of discharge exist, namely, the E mode at low RF power and H mode at high RF power. Mode transition that occurs is accompanied by abrupt changes in both electrical and plasma characteristics. Hysteresis is observed in the mode transitions and has a minimum at 0.1 mbar. The resistance reflected into the …

Performance Analysis Of Srcp Image Based Sound Source Detection Algorithms, Praveen Reddy Nalavolu

University of Kentucky Master's Theses

Steered Response Power based algorithms are widely used for finding sound source location using microphone array systems. SRCP-PHAT is one such algorithm that has a robust performance under noisy and reverberant conditions. The algorithm creates a likelihood function over the field of view. This thesis employs image processing methods on SRCP-PHAT images, to exploit the difference in power levels and pixel patterns to discriminate between sound source and background pixels. Hough Transform based ellipse detection is used to identify the sound source locations by finding the centers of elliptical edge pixel regions typical of source patterns. Monte Carlo simulations of …

Theoretical Modeling And Analysis Of Ammonia Gas Sensing Properties Of Vertically Aligned Multiwalled Carbon Nanotube Resistive Sensors And Enhancing Their Sensitivity, Shripriya Darshini Poduri

University of Kentucky Master's Theses

Vertically aligned Multiwalled Carbon Nanotubes (MWCNTs) were grown in the pores of Anodized Aluminum Oxide (AAO) templates and investigated for resistive sensor applications. High Sensitivity of 23% to low concentration (100 ppm) of ammonia was observed. An equivalent circuit model was developed to understand the current flow path in the resistive sensor. This helped us in achieving high sensitivities through amorphous carbon (a-C) layer thickness tailoring by employing post-growth processing techniques like plasma etching.

A simulation model in MATLAB was developed to calculate the device resistance and the change in the sensitivity as a function of device parameters. The steady …

Testing Program For Kysat‐1, Jason Robert Bratcher

University of Kentucky Master's Theses

Years of success in the aerospace industry has taught Kentucky Space several lessons. This thesis will summarize the accomplishments in an attempt to formulate a well-defined program for designing and testing small spacecraft in an environment with strict financial restraints. The motivation for producing this well-defined platform for testing small spacecraft arose when Kentucky Space became the liaison between NASA and its customers for the NanoRacks and CubeLab module program. Having a solid program for testing small spacecraft will allow future student programs to easily set standards for experiment payloads. Also by discussing obstacles for smaller programs such as restraints …

Verilog Design And Fpga Prototype Of A Nanocontroller System, Akshay Vummannagari

University of Kentucky Master's Theses

Many new fabrication technologies, from nanotechnology and MEMS to printed organic semiconductors, center on constructing arrays of large numbers of sensors, actuators, or other devices on a single substrate. The utility of such an array could be greatly enhanced if each device could be managed by a programmable controller and all of these controllers could coordinate their actions as a massively-parallel computer. Kentucky Architecture nanocontroller array with very low per controller circuit complexity can provide efficient control of nanotechnology devices.

This thesis provides a detailed description of the control hierarchy of a digital system needed to build "nanocontrollers" suitable for …

Gold Nanospheres And Gold Nanorods As Localized Surface Plasmon Resonance Sensors, Akil Mannan Matcheswala

University of Kentucky Master's Theses

A novel localized surface plasmon resonance (LSPR) sensor that differentiates between background refractive index changes and surface-binding of a target analyte (e.g. a target molecule, protein, or bacterium) is presented. Standard, single channel LSPR sensors cannot differentiate these two effects as their design allows only one mode to be coupled. This novel technique uses two surface plasmon modes to simultaneously measure surface binding and solution refractive index changes. This increases the sensitivity of the sensor.

Different channels or modes can be created in sensors with the introduction of gold nanospheres or gold nanorods that act as receptor mechanisms. Once immobilization …

Issues Related To The Numerical Implementation Of A Sparse Method For The Solution Of Volume Integral Equations At Low Frequencies, Kiran Arcot

University of Kentucky Master's Theses

Computational electromagnetic modeling involves generating system matrices by discretizing integral equations and solving the resulting system of linear equations. Many methods of solving the system of linear equations exist and one such method is the factorization of the matrix using the so called local-global solution (LOGOS) modes. Computer codes to perform the discretization of the integral equations, filling of the matrix, and the subsequent LOGOS factorization have previously been developed by others. However, these codes are limited to complex double precision arithmetic only.

This thesis extends and expands the existing computer by creating a more general implementation that is able …

A Novel Message Routing Layer For The Communication Management Of Distributed Embedded Systems, Darren Jacob Brown

University of Kentucky Master's Theses

Fault tolerant and distributed embedded systems are research areas that have the interest of such entities as NASA, the Department of Defense, and various other government agencies, corporations, and universities. Taking a system and designing it to work in the presence of faults is appealing to these entities as it inherently increases the reliability of the deployed system. There are a few different fault tolerant techniques that can be implemented in a system design to handle faults as they occur. One such technique is the reconfiguration of a portion of the system to a redundant resource. This is a difficult …