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Analysis, Design And Efficiency Optimization Of Power Converters For Renewable Energy Applications, Xi Chen
Analysis, Design And Efficiency Optimization Of Power Converters For Renewable Energy Applications, Xi Chen
Electronic Theses and Dissertations
DC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with the applications where the isolation is required, either these topologies should be modified, or alternative topologies are needed. Among various isolated DC-DC converters, the LLC resonant converter is an attractive selection due …
Reconfigurable Reflectarray Antennas With Bandwidth Enhancement For High Gain, Beam-Steering Applications, Michael Trampler
Reconfigurable Reflectarray Antennas With Bandwidth Enhancement For High Gain, Beam-Steering Applications, Michael Trampler
Electronic Theses and Dissertations
Reconfigurable reflectarrays are a class of antennas that combine the advantages of traditional parabolic antennas and phased array antennas. Chapter 1 discusses the basic operational theory of reflectarrays and their design. A review of previous research and the current status is also presented. Furthermore the inherent advantages and disadvantages of the reflectarray topography are presented. In chapter 2, a BST-integrated reflectarray operating at Ka band is presented. Due to the monolithic integration of the tuning element, this design is then extended to V band where a novel interdigital gap configuration is utilized. Finally to overcome loss and phase limitations of …
Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang
Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang
Electronic Theses and Dissertations
Wireless communication systems have rapidly evolved over the past decade which has led to an explosion of mobile data traffic. Since more and more wireless devices and sensors are being connected, the transition from the current 4G/LTE mobile network to 5G is expected to happen within the next decade. In order to improve signal-to-noise ratio (SNR), system capacity, and link budget, beam steerable antenna arrays are desirable due to their advantage in spatial selectivity and high directivity. Electronically steerable parasitic array radiator (ESPAR) that can achieve low-cost continuously beamsteering using varactor diodes have attracted a lot of attention. This dissertation …
Programmable Low Loss Orthogonal Frequency Coded Surface Acoustic Wave Correlator Filters, Marshall Smith
Programmable Low Loss Orthogonal Frequency Coded Surface Acoustic Wave Correlator Filters, Marshall Smith
Electronic Theses and Dissertations
Simultaneous Transmit and Receive (STAR) communication is being developed as a means of improving spectral efficiency in wireless communication systems. If the obstacle of self-interference can be sufficiently overcome, it is possible to double the spectral efficiency of an equivalent time or frequency division duplexed system. Spread spectrum techniques can reduce self-interference by using orthogonal or pseudo-orthogonal codes to encode the transmit signal and decode the receive signal. Hardware correlator filters are developed for use with STAR radio systems using orthogonal frequency coded (OFC) surface acoustic wave (SAW) devices. OFC is a type of spread spectrum communication that can be …
Semiconductor Device Modeling, Simulation, And Failure Prediction For Electrostatic Discharge Conditions, Hang Li
Electronic Theses and Dissertations
Electrostatic Discharge (ESD) caused failures are major reliability issues in IC industry. Device modeling for ESD conditions is necessary to evaluate ESD robustness in simulation. Although SPICE model is accurate and efficient for circuit simulations in most cases, devices under ESD conditions operate in abnormal status. SPICE model cannot cover the device operating region beyond normal operation. Thermal failure is one of the main reasons to cause device failure under ESD conditions. A compact model is developed to predict thermal failure with circuit simulators. Instead of considering the detailed failure mechanisms, a failure temperature is introduced to indicate device failure. …
Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi
Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi
Electronic Theses and Dissertations
This dissertation focuses on information recovery under two general types of sensing constraints and hardware limitations that arise in practical data acquisition systems. We study the effects of these practical limitations in the context of signal recovery problems from interferometric measurements such as for optical mode analysis. The first constraint stems from the limited number of degrees of freedom of an information gathering system, which gives rise to highly constrained sensing structures. In contrast to prior work on compressive signal recovery which relies for the most part on introducing additional hardware components to emulate randomization, we establish performance guarantees for …
Artificial Neuron Using Mos2/Graphene Threshold Switching Memristor, Hirokjyoti Kalita
Artificial Neuron Using Mos2/Graphene Threshold Switching Memristor, Hirokjyoti Kalita
Electronic Theses and Dissertations
With the ever-increasing demand for low power electronics, neuromorphic computing has garnered huge interest in recent times. Implementing neuromorphic computing in hardware will be a severe boost for applications involving complex processes such as pattern recognition. Artificial neurons form a critical part in neuromorphic circuits, and have been realized with complex complementary metal–oxide–semiconductor (CMOS) circuitry in the past. Recently, insulator-to-metal-transition (IMT) materials have been used to realize artificial neurons. Although memristors have been implemented to realize synaptic behavior, not much work has been reported regarding the neuronal response achieved with these devices. In this work, we study the IMT in …
Different Facial Recognition Techniques In Transform Domains, Taif Al Obaidi
Different Facial Recognition Techniques In Transform Domains, Taif Al Obaidi
Electronic Theses and Dissertations
The human face is frequently used as the biometric signal presented to a machine for identification purposes. Several challenges are encountered while designing face identification systems. The challenges are either caused by the process of capturing the face image itself, or occur while processing the face poses. Since the face image not only contains the face, this adds to the data dimensionality, and thus degrades the performance of the recognition system. Face Recognition (FR) has been a major signal processing topic of interest in the last few decades. Most common applications of the FR include, forensics, access authorization to facilities, …
High Quality Gate Dielectric/Mos2 Interfaces Probed By The Conductance Method, Adithi Pandrahal Krishnaprasad Sharada
High Quality Gate Dielectric/Mos2 Interfaces Probed By The Conductance Method, Adithi Pandrahal Krishnaprasad Sharada
Electronic Theses and Dissertations
Two-dimensional materials provide a versatile platform for various electronic and optoelectronic devices, due to their uniform thickness and pristine surfaces. We probe the superior quality of 2D/2D and 2D/3D interfaces by fabricating molybdenum disulfide (MoS2)-based field effect transistors having hexagonal boron nitride (h-BN) and Al2O3 as the top gate dielectrics. An extremely low trap density of ~7x10^10 states/cm2-eV is extracted at the 2D/2D interfaces with h-BN as the top gate dielectric on the MoS2 channel. 2D/3D interfaces with Al2O3 as the top gate dielectric and SiOx as the nucleation layer exhibit trap densities between 7x10^10 and 10^11 states/cm2-eV, which is …
Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh
Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh
Electronic Theses and Dissertations
In this work, we demonstrate an InGaAsP multiple quantum well tunable laser diode that amalgamates two gain sections with different bandgap energies. This is achieved using selective area intermixing of the multiple quantum wells, and impurity-free vacancy induced disordering. When different current combination is injected into each section, that leads to a laser wavelength peak whose position depends on the relative magnitudes of the two injected currents. The laser wavelength can be fine-tuned from 1538 nm to 1578 nm with relatively constant output power. The free spectral range FSR of the tunable laser found to be 0.25 nm. This tunable …
Design Of Low-Capacitance Electrostatic Discharge (Esd) Protection Devices In Advanced Silicon Technologies., Aihua Dong
Design Of Low-Capacitance Electrostatic Discharge (Esd) Protection Devices In Advanced Silicon Technologies., Aihua Dong
Electronic Theses and Dissertations
Electrostatic discharge (ESD) related failure is a major IC reliability concern and this is particularly true as technology continues shrink to nano-metric dimensions. ESD design window research shows that ESD robustness of victim devices keep decreasing from 350nm bulk technology to 7nm FinFET technologies. In the meantime, parasitic capacitance of ESD diode with same It2 in FinFET technologies is approximately 3X compared with that in planar technologies. Thus transition from planar to FinFET technology requires more robust ESD protection however the large parasitic capacitance of ESD protection cell is problematic in high-speed interface design. To reduce the parasitic capacitance, a …
Enhancement Of Antenna Array Performance Using Reconfigurable Slot-Ring Antennas And Integrated Filter/Antennas, Tianjiao Li
Enhancement Of Antenna Array Performance Using Reconfigurable Slot-Ring Antennas And Integrated Filter/Antennas, Tianjiao Li
Electronic Theses and Dissertations
As modern communication system technology develops, the demand for devices with smaller size, higher efficiency, and more functionality has increased dramatically. In addition, highly integrated RF-front-end modules with a reduced footprint and less transition loss between cascaded devices are desirable in most advanced wireless communication systems. Antenna arrays are widely used in wireless communication systems due to their high directivity and beam steering capability. Moreover, antenna arrays are preferred in mobile communication systems for diversity reception to reduce signal fading effects. In order to meet the various requirements of rapidly developing wireless communication systems, low cost, compact, multifunctional integrated antenna …
Ldmos Power Transistor Design And Evaluation Using 2d And 3d Device Simulation, Aiman Salih
Ldmos Power Transistor Design And Evaluation Using 2d And 3d Device Simulation, Aiman Salih
Electronic Theses and Dissertations
The benefit of the super-junction (SJ) technique and the use of a floating P layer for low voltage (30 V) laterally double-diffused metal oxide semiconductor (LDMOS) transistors are investigated in this thesis using Sentaurus TCAD simulation software. Optimizations to the SJ LDMOS were attempted such as adding a buffer layer to the device, but simulation and theoretical evidence point out that the benefits of the SJ technique are marginal at the 30 V application. A replacement for the SJ technique was sought, the floating P structure proved to be a good solution at the low voltage range due to its …
High Average Power Nanosecond Pulsed Tm:Fiber Laser For Pumping An Optical Parametric Oscillator, Ali Abdulfattah
High Average Power Nanosecond Pulsed Tm:Fiber Laser For Pumping An Optical Parametric Oscillator, Ali Abdulfattah
Electronic Theses and Dissertations
Thulium-doped fiber lasers operating with wavelengths in the vicinity of 2 µm are useful for several emerging applications including generating mid-IR light via nonlinear frequency conversion. In this study we describe the design and construction of a thulium fiber laser system comprising a master oscillator and a power amplifier. The first stage is a Q-switched, thulium-doped photonic crystal fiber oscillator utilizing an acousto-optic modulator to produce 65-80 nanosecond pulses. A diffraction grating in the cavity provides wavelength tunability from 1.8 – 2µm. The oscillator produced up to 3 W of average power and 150 µJ pulse energies, corresponding to 2.3 …
Smart Grasping Using Laser And Tactile Array Sensors For Ucf-Manus- An Intelligent Assistive Robotic Manipulator, Kiran Prakash
Smart Grasping Using Laser And Tactile Array Sensors For Ucf-Manus- An Intelligent Assistive Robotic Manipulator, Kiran Prakash
Electronic Theses and Dissertations
This thesis presents three improvements in the UCF MANUS Assistive Robotic Manipulator's grasping abilities. Firstly, the robot can now grasp objects that are deformable, heavy and have uneven contact surfaces without undergoing slippage during robotic operations, e.g. paper cup, filled water bottle. This is achieved by installing a high precision non-contacting Laser sensor1 that runs with an algorithm that processes raw-input data from the sensor, registers smallest variation in the relative position of the object with respect to the gripper. Secondly, the robot can grasp objects that are as light and small as single cereal grain without deforming it. To …
Performance Evaluation Of Connectivity And Capacity Of Dynamic Spectrum Access Networks, Osama Al-Tameemi
Performance Evaluation Of Connectivity And Capacity Of Dynamic Spectrum Access Networks, Osama Al-Tameemi
Electronic Theses and Dissertations
Recent measurements on radio spectrum usage have revealed the abundance of under- utilized bands of spectrum that belong to licensed users. This necessitated the paradigm shift from static to dynamic spectrum access (DSA) where secondary networks utilize unused spectrum holes in the licensed bands without causing interference to the licensed user. However, wide scale deployment of these networks have been hindered due to lack of knowledge of expected performance in realistic environments and lack of cost-effective solutions for implementing spectrum database systems. In this dissertation, we address some of the fundamental challenges on how to improve the performance of DSA …
Microgrid Control And Protection: Stability And Security, Morteza Keshavarztalebi
Microgrid Control And Protection: Stability And Security, Morteza Keshavarztalebi
Electronic Theses and Dissertations
When the microgrid disconnects from the main grid in response to, say, upstream disturbance or voltage fluctuation and goes to islanding mode, both voltage and frequency at all locations in the microgrid have to be regulated to nominal values in a short amount of time before the operation of protective relays. Motivated by this, we studied the application of intelligent pinning of distributed cooperative secondary control of distributed generators in islanded microgrid operation in a power system. In the first part, the problem of single and multi-pinning of distributed cooperative secondary control of DGs in a microgrid is formulated. It …
Design And Characterization Of System Level Electrostatic Discharge (Esd) Protection Solutions, Yunfeng Xi
Design And Characterization Of System Level Electrostatic Discharge (Esd) Protection Solutions, Yunfeng Xi
Electronic Theses and Dissertations
Electrostatic Discharges (ESD) are one of the main reliability threats in modern electronics. Design, implementation, and characterization of ESD and transient protection of these modern electronics are increasingly challenging due to the process, packaging and cost constraints. Growing communication between ‘objects’ to be sensed and controlled remotely is creating opportunities for greater integration with computer systems, resulting in improved efficiency, accuracy and economic benefits across existing and emerging network infrastructures. This tendency is driving an expansion in data communication as well as industrial applications environment. To keep up with the interconnectivity expansion, the industry requires new devices to support more …
Study Of Novel Power Semiconductor Devices For Performance And Reliability., Karthik Padmanabhan
Study Of Novel Power Semiconductor Devices For Performance And Reliability., Karthik Padmanabhan
Electronic Theses and Dissertations
Power Semiconductor Devices are crucial components in present day power electronic systems. The performance and efficiency of the devices have a direct correlation with the power system efficiency. This dissertation will examine some of the components that are commonly used in a power system, with emphasis on their performance characteristics and reliability. In recent times, there has a proliferation of charge balance devices in high voltage discrete power devices. We examine the same charge balance concept in a fast recovery diode and a MOSFET. This is crucial in the extending system performance at compact dimensions. At smaller device and system …
Investigation Of The Effect Of Rain On Sea Surface Salinity, Andrea Santos Garcia
Investigation Of The Effect Of Rain On Sea Surface Salinity, Andrea Santos Garcia
Electronic Theses and Dissertations
The Aquarius/SAC-D mission provided Sea Surface Salinity (SSS), globally over the ocean, for almost 4 years. As a member of the AQ/SAC-D Cal/Val team, the Central Florida Remote Sensing Laboratory has analyzed these salinity measurements in the presence of precipitation and has noted the high correlation between the spatial patterns of reduced SSS and the spatial distribution of rain. It was determined that this is the result of a cause and effect relation, and not SSS measurement errors. Thus, it is important to understand these salinity changes due to seawater dilution by rain and the associated near-surface salinity strati?cation. This …
Rf Circuit Designs For Reliability And Process Variability Resilience, Ekavut Kritchanchai
Rf Circuit Designs For Reliability And Process Variability Resilience, Ekavut Kritchanchai
Electronic Theses and Dissertations
Complementary metal oxide semiconductor (CMOS) radio frequency (RF) circuit design has been an ever-lasting research field. It has gained so much attention since RF circuits offer high mobility and wide-band efficiency, while CMOS technology provides the advantage of low cost and high integration capability. At the same time, CMOS device size continues to scale to the nanometer regime. Reliability issues with RF circuits have become more challenging than ever before. Reliability mechanisms, such as gate oxide breakdown, hot carrier injection, negative bias temperature instability, have been amplified as the device size shrinks. In addition, process variability becomes a new design …
Model Selection Via Racing, Tiantian Zhang
Model Selection Via Racing, Tiantian Zhang
Electronic Theses and Dissertations
Model Selection (MS) is an important aspect of machine learning, as necessitated by the No Free Lunch theorem. Briefly speaking, the task of MS is to identify a subset of models that are optimal in terms of pre-selected optimization criteria. There are many practical applications of MS, such as model parameter tuning, personalized recommendations, A/B testing, etc. Lately, some MS research has focused on trading off exactness of the optimization with somewhat alleviating the computational burden entailed. Recent attempts along this line include metaheuristics optimization, local search-based approaches, sequential model-based methods, portfolio algorithm approaches, and multi-armed bandits. Racing Algorithms (RAs) …
Design And Optimization Of Superjunction Vertical Dmos Power Transistors Using Sentaurus Device Simulation, Raul Mendoza Macias
Design And Optimization Of Superjunction Vertical Dmos Power Transistors Using Sentaurus Device Simulation, Raul Mendoza Macias
Electronic Theses and Dissertations
Vertical double-diffused metal oxide semiconductor (VDMOS) power transistor has been studied. The use of superjunction (SJ) in the drift region of VDMOS has been evaluated using three-dimensional device simulation. All relevant physical models in Sentaurus are turned on. The VDMOS device doping profile is obtained from process simulation. The superjunction VDMOS performance in off-state breakdown voltage and specific on-resistance is compared with that in conventional VDMOS structure. In addition, electrical parameters such as threshold voltage and charge balance are also examined. Increasing the superjunction doping in the drift region of VDMOS reduces the on-resistance by 26%, while maintaining the same …
Impact Of Wireless Channel Uncertainty Upon M-Ary Distributed Detection Systems., Zahra Hajibabaei Najafabadi
Impact Of Wireless Channel Uncertainty Upon M-Ary Distributed Detection Systems., Zahra Hajibabaei Najafabadi
Electronic Theses and Dissertations
We consider a wireless sensor network (WSN), consisting of several sensors and a fusion center (FC), which is tasked with solving an $M$-ary hypothesis testing problem. Sensors make $M$-ary decisions and transmit their digitally modulated decisions over orthogonal channels, which are subject to Rayleigh fading and noise, to the FC. Adopting Bayesian optimality criterion, we consider training and non-training based distributed detection systems and investigate the effect of imperfect channel state information (CSI) on the optimal maximum a posteriori probability (MAP) fusion rules and detection performance, when the sum of training and data symbol transmit powers is fixed. Our results …
Post Conversion Correction Of Non-Linear Mismatches For Time Interleaved Analog-To-Digital Converters, Charna Parkey
Post Conversion Correction Of Non-Linear Mismatches For Time Interleaved Analog-To-Digital Converters, Charna Parkey
Electronic Theses and Dissertations
Time Interleaved Analog-to-Digital Converters (TI-ADCs) utilize an architecture which enables conversion rates well beyond the capabilities of a single converter while preserving most or all of the other performance characteristics of the converters on which said architecture is based. Most of the approaches discussed here are independent of architecture; some solutions take advantage of specific architectures. Chapter 1 provides the problem formulation and reviews the errors found in ADCs as well as a brief literature review of available TI-ADC error correction solutions. Chapter 2 presents the methods and materials used in implementation as well as extend the state of the …
General Vector Explicit - Impact Time And Angle Control Guidance, Loren Robinson
General Vector Explicit - Impact Time And Angle Control Guidance, Loren Robinson
Electronic Theses and Dissertations
This thesis proposes and evaluates a new cooperative guidance law called General Vector Explicit - Impact Time and Angle Control Guidance (GENEX-ITACG). The motivation for GENEX-ITACG came from an explicit trajectory shaping guidance law called General Vector Explicit Guidance (GENEX). GENEX simultaneously achieves design specifications on miss distance and terminal missile approach angle while also providing a design parameter that adjusts the aggressiveness of this approach angle. Encouraged by the applicability of this user parameter, GENEX-ITACG is an extension that allows a salvo of missiles to cooperatively achieve the same objectives of GENEX against a stationary target through the incorporation …
Design, Characterization And Analysis Of Component Level Electrostatic Discharge (Esd) Protection Solutions, Sirui Luo
Electronic Theses and Dissertations
Electrostatic Discharges (ESD) is a significant hazard to electronic components and systems. Based on a specific process technology, a given circuit application requires a customized ESD consideration that meets all the requirements such as the core circuit's operating condition, maximum accepted leakage current, breakdown conditions for the process and overall device sizes. In every several years, there will be a new process technology becomes mature, and most of those new technology requires custom design of effective ESD protection solution. And usually the design window will shrinks due to the evolving of the technology becomes smaller and smaller. The ESD related …
Modified System Design And Implementation Of An Intelligent Assistive Robotic Manipulator, Nicholas Paperno
Modified System Design And Implementation Of An Intelligent Assistive Robotic Manipulator, Nicholas Paperno
Electronic Theses and Dissertations
This thesis presents three improvements to the current UCF MANUS systems. The first improvement modifies the existing fine motion controller into PI controller that has been optimized to prevent the object from leaving the view of the cameras used for visual servoing. This is achieved by adding a weight matrix to the proportional part of the controller that is constrained by an artificial ROI. When the feature points being used are approaching the boundaries of the ROI, the optimized controller weights are calculated using quadratic programming and added to the nominal proportional gain portion of the controller. The second improvement …
Design Of High-Efficiency Rare-Earth Permanent Magnet Synchronous Motor And Drive System, Hanzhou Liu
Design Of High-Efficiency Rare-Earth Permanent Magnet Synchronous Motor And Drive System, Hanzhou Liu
Electronic Theses and Dissertations
Utilization of renewable energy has become the future trend in the trucking industry. Electrical power generated from renewable energy can replace part of the fuel usage. There is usually limited space for storing on-board battery. Thus, to better utilize the battery power, it becomes critical to have an efficient energy conversion device that can transfer energy from battery to amenities such as air conditioner, microwave, TV, mini refrigerator, etc. In this dissertation, a designed permanent magnet synchronous motor (PMSM) can be such energy conversion device for an electric Auxiliary Power Unit (APU) application, which will have a desired output power …
Performance Optimization Of Lateral-Mode Thin-Film Piezoelectric-On-Substrate Resonant Systems, Hedy Fatemi
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 …