Electrical and Electronics Commons^™

Numerical Modeling Of Cds/Znxcd1-Xte Solar Cell, Farhana Anwar

Open Access Theses & Dissertations

Device modeling and simulation studies of CdS/ZnxCd1-xTe thin film solar cell have been carried out. A variety of graded band gap structures are examined. Incorporation of back electron reflector layer to improve open circuit voltage and carrier collection of CdTe solar cell was investigated. Device physics and performance determining parameters for different band gap profiles were analyzed. Based on simulation results, an optimal graded band gap structure for CdS/ZnxCd1-xTe solar cell is proposed. Performance of optimally graded band gap cell is superior to that of uniform bandgap cell.

Equating A Car Alternator With The Generated Voltage Equation, Ervin Carrillo

Electrical Engineering

No abstract provided.

Optical Mode Pattern Study Of Gan Based Leds With And Without Nanoscale Top Grating, Gregory Chavoor

Electrical Engineering

This study analyzes optical confinement factor and light emitting mode order for three different GaN LEDs: a conventional LED, thin Film LED, and thin Film LED with a photonic crystal (PhC) grating. For the first structure, we increase the thickness of Al_xGa_1-xN from 0 to 600nm, alter the x composition in Al_xGa_1-xN from 0.05 to 0.2 in steps of 0.05, and adjust the p-GaN and n-GaN thicknesses each from 0 to 200nm. For the second structure, we alter the n-GaN substrate thickness from 300-1000nm in steps of 100nm and 1000-4000nm in steps …

Brightness Temperature Calibration Of Sac-D/Aquarius Microwave Radiometer (Mwr), Sayak Krishna Biswas

Electronic Theses and Dissertations

The Aquarius/SAC-D joint international science mission, between the National Aeronautics and Space Administration (NASA) of United States and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE), was launched on a polarorbiting satellite on June 10, 2011. This mission of discovery will provide measurements of the global sea surface salinity, which contributes to understanding climatic changes in the global water cycle and how these variations influence the general ocean circulation. The Microwave Radiometer (MWR), a three channel Dicke radiometer operating at 23.8 GHz H-Pol and 36.5 GHz V-& H-Pol provided by CONAE, will complement Aquarius (NASA’s L-band radiometer/scatterometer) by …

High Performance Low Voltage Power Mosfet For High-Frequency Synchronous Buck Converters, Boyi Yang

Electronic Theses and Dissertations

Power management solutions such as voltage regulator (VR) mandate DC-DC converters with high power density, high switching frequency and high efficiency to meet the needs of future computers and telecom equipment. The trend towards DC-DC converters with higher switching frequency presents significant challenges to power MOSFET technology. Optimization of the MOSFETs plays an important role in improving low-voltage DC-DC converter performance. This dissertation focuses on developing and optimizing high performance low voltage power MOSFETs for high frequency applications. With an inherently large gate charge, the trench MOSFET suffers significant switching power losses and cannot continue to provide sufficient performance in …

Design, Characterization And Analysis Of Electrostatic Discharge (Esd) Protection Solutions In Emerging And Modern Technologies, Wen Liu

Electronic Theses and Dissertations

Electrostatic Discharge (ESD) is a significant hazard to electronic components and systems. Based on a specific processing technology, a given circuit application requires a customized ESD consideration that includes the devices’ operating voltage, leakage current, breakdown constraints, and footprint. As new technology nodes mature every 3-5 years, design of effective ESD protection solutions has become more and more challenging due to the narrowed design window, elevated electric field and current density, as well as new failure mechanisms that are not well understood. The endeavor of this research is to develop novel, effective and robust ESD protection solutions for both emerging …

A Microwave Radiometer Roughness Correction Algorithm For Sea Surface Salinity Retrieval, Yazan Henry Hejazin

Electronic Theses and Dissertations

The Aquarius/SAC-D is an Earth Science remote sensing satellite mission to measure global Sea Surface Salinity (SSS) that is sponsored by the NASA and the Argentine Space Agency (CONAE). The prime remote sensor is the Aquarius (AQ) L-band radiometer/scatterometer, which measures the L-band emitted blackbody radiation (brightness temperature) from the ocean. The brightness temperature at L-band is proportional to the ocean salinity as well as a number of physical parameters including ocean surface wind speed. The salinity retrieval algorithm make corrections for all other parameters before retrieving salinity, and the greatest of these is the increased brightness temperature due to …

Complex-Valued Adaptive Digital Signal Enhancement For Applications In Wireless Communication Systems, Ying Liu

Electronic Theses and Dissertations

In recent decades, the wireless communication industry has attracted a great deal of research efforts to satisfy rigorous performance requirements and preserve high spectral efficiency. Along with this trend, I/Q modulation is frequently applied in modern wireless communications to develop high performance and high data rate systems. This has necessitated the need for applying efficient complex-valued signal processing techniques to highly-integrated, multi-standard receiver devices. In this dissertation, novel techniques for complex-valued digital signal enhancement are presented and analyzed for various applications in wireless communications. The first technique is a unified block processing approach to generate the complex-valued conjugate gradient Least …

Study Of Design For Reliability Of Rf And Analog Circuits, Hongxia Tang

Electronic Theses and Dissertations

Due to continued device dimensions scaling, CMOS transistors in the nanometer regime have resulted in major reliability and variability challenges. Reliability issues such as channel hot electron injection, gate dielectric breakdown, and negative bias temperature instability (NBTI) need to be accounted for in the design of robust RF circuits. In addition, process variations in the nanoscale CMOS transistors are another major concern in today‟s circuits design. An adaptive gate-source biasing scheme to improve the RF circuit reliability is presented in this work. The adaptive method automatically adjusts the gate-source voltage to compensate the reduction in drain current subjected to various …

Transient Safe Operating Area (Tsoa) For Esd Applications, Slavica Malobabic

Electronic Theses and Dissertations

A methodology to obtain design guidelines for gate oxide input pin protection and high voltage output pin protection in Electrostatic Discharge (ESD) time frame is developed through measurements and Technology Computer Aided Design (TCAD). A set of parameters based on transient measurements are used to define Transient Safe Operating Area (TSOA). The parameters are then used to assess effectiveness of protection devices for output and input pins. The methodology for input pins includes establishing ESD design targets under Charged Device Model (CDM) type stress in low voltage MOS inputs. The methodology for output pins includes defining ESD design targets under …

Analysis And Design Optimization Of Resonant Dc-Dc Converters, Xiang Fang

Electronic Theses and Dissertations

The development in power conversion technology is in constant demand of high power efficiency and high power density. The DC-DC power conversion is an indispensable stage for numerous power supplies and energy related applications. Particularly, in PV micro-inverters and front-end converter of power supplies, great challenges are imposed on the power performances of the DC-DC converter stage, which not only require high efficiency and density but also the capability to regulate a wide variation range of input voltage and load conditions. The resonant DC-DC converters are good candidates to meet these challenges with the advantages of achieving soft switching and …

Characterization, Morphology, Oxidation, And Recession Of Silicon Nanowires Grown By Electroless Process, Robert G. Mertens

Electronic Theses and Dissertations

This dissertation presents heretofore undiscovered properties of Silicon Nanowires (SiNWs) grown by electroless process and presents mathematical solutions to the special problems of the oxidation and diffusion of dopants for SiNWs. Also presented here is a mathematical description of morphology of oxidized SiNWs. This dissertation is comprised of several discussions relating to SiNWs growth, oxidation, morphology and doping. In here is presented work derived from a long-term study of SiNWs. Several important aspects of SiNWs were investigated and the results published in journals and conference papers. The recession of SiNWs was heretofore unreported by other research groups. In our investigations, …

Bootstrapping Cognitive Radio Networks, Brent Horine

Electronic Theses and Dissertations

Cognitive radio networks promise more efficient spectrum utilization by leveraging degrees of freedom and distributing data collection. The actual realization of these promises is challenged by distributed control, and incomplete, uncertain and possibly conflicting knowledge bases. We consider two problems in bootstrapping, evolving, and managing cognitive radio networks. The first is Link Rendezvous, or how separate radio nodes initially find each other in a spectrum band with many degrees of freedom, and little shared knowledge. The second is how radio nodes can negotiate for spectrum access with incomplete information. To address the first problem, we present our Frequency Parallel Blind …

A New Quasi Resonant Dc-Link For Photovoltaic Micro-Inverters, Anna Grishina

Electronic Theses and Dissertations

PV Inverters have the task of tracking the maximum power point (MPP), and regulating the solar energy generation to this optimal operation point. The second task is the conversion of direct current produced by the solar modules into alternating current compatible with the grid. A new inverter approach such as a single phase micro inverter is emerging aimed to overcome some of the challenges of centralized inverters. As a counterpart to the central inverter, a micro inverter is a small compact module attached directly to each solar panel. To provide for the constantly increasing demand for a small size, light …

Wireless Power Transfer For Space Applications: System Design And Electromagnetic Compatibility Compliance Of Radiated Emissions, Ramos Gabriel Vazquez

Electronic Theses and Dissertations

This dissertation evaluates the possibility of wireless power transfer (WPT) systems for space applications, with an emphasis in launch vehicles (rockets). After performing literature review for WPT systems, it was identified that magnetic resonance provides the more suited set of characteristics for this application. Advanced analysis, simulation and testing were performed to magnetic resonance WPT systems to acquire system performance insight. This was accomplished by evaluating/varying coupling configuration, load effects and magnetic element physical characteristics (i.e. wire material, loop radius, etc.). It was identified by analysis, circuit simulation and testing that the best coupling configuration for this application was series-series …

A Distributed Model Predictive Control For Multi-Agent Multi-Rate Systems, Samira Roshany-Yamchi

Theses

In this thesis, a new method is proposed to control multi-agent multi-rate systems with linear dynamics that are coupled via inputs and states. These systems are multi-rate in the sense that either output measurements or input updates are not available at certain sampling. Such systems can arise when the number of sensors is less than the number of variables to be controlled or when measurements of outputs cannot be completed simultaneously because of applicational limitations. The multi-rate nature gives rise to lack of information which will cause uncertainty in the system's performance.

The proposal is to control such systems with …

A Service Provisioning Architecture For Next Generation Wireless Sensor Networks - The Wsn Cloud, Muhammad Sohaib Aslam

Theses

The relentless demand for pervasive computing in our everyday lives has led to and will continue to drive the roll out of large scale embedded systems in the form of Wireless Sensor Networks or WSNs in our environment. This in turn drives the need for reusable, flexible and manageable WSN infrastructures. To simplify system operation and maintenance as well as to reduce costs, WSNs must become an infrastructure that is capable of providing services to multiple end users concurrently rather than having to roll out individual infrastructures for specific purposes as is typical nowadays. This thesis presents the concept of …

Design And Production Aspects Of An Electroluminescent Segment Display, Veronica Kopp, Chris Nixon

Graphic Communication

The purpose of this study was to get a better understanding of the different ways printed circuits could be constructed and then implemented into creative, visual designs for printed electroluminescent displays. A variety of circuit design variables, such as area and length, were tested that will help create solutions for printed electronics.

This study tested different variables of circuit design, such as length of silver traces and the size of the image area, to help optimize ways to build a printed circuit. Then, findings were implemented into a segmented graphic display in order to analyze innovative ways to utilize multiple …

Voltage Rise Mitigation In A Weak Distribution Network Due To The Impact Of Distributed Generation, Donal Caples

Theses

There are numerous aspects of a distribution network that must be studied in order to determine the maximum size of distributed generation that can be accommodated on the distribution network before supply standards are breached. Voltage rise is one of the main aspects of concern when connecting a distributed generator to a distribution network and this thesis develops the understanding of this phenomenon and concludes with a real life study.

Mathematical and computer simulation software examples within this thesis demonstrate how voltage rise can be reduced to the maximum allowable limit, a major concern if the capacity of a distributed …

Theoretical And Experimental Analysis Of Mems Ohmic Switch Design And Control For Reliability Improvement, Cuong Do

Theses

MEMS devices are micromechanical components fabricated using semiconductor fabrication technologies. With advanced functionalities and miniaturization, MEMS devices are being employed in a wide variety of applications, especially in mobile networks. The MEMS ohmic switch is one of the most promising MEMS devices and has the same principle of a mechanical moving switch to manipulate an electrical signal. Due to the existence of mechanical movement, and its compactness, reliability issues have been observed as the main barrier to commercialisation.

This thesis addresses the key issue of reliability in the rapidly expanding area of MEMS. In particular, MEMS ohmic switches are considered. …