Electronic Devices and Semiconductor Manufacturing Commons^™

High Voltage Direct Current Energy Transmission Using Modular Multilevel Converters, David Alejandro Guzman Pinzon

Graduate Theses and Dissertations

This thesis focus on high voltage direct current (HVdc) energy transmission using modular multilevel converter (MMC) based terminals. It provides a brief comparison between different HVdc technologies, focusing on voltage source converters (HVdc-VSC) with the MMC-based terminal emerging as the topology of choice for ratings less than 1 GW. The controllers for a two-terminal HVdc-link are analyzed and Matlab/Simulink^TM simulation models are presented. The simplified models and full Matlab/Simulink^TM based model are used to select the gains for the MMC controllers. Simulation results carried out on the full model validated the proposed methodologies. A new control technique that …

2-Dimensional Personal Motion Energy Harvester For Low Power Electronics, Manuel Gutierrez, Sean Scott, Dimitrios Peroulis

The Summer Undergraduate Research Fellowship (SURF) Symposium

In a lab, it becomes crucial to have a way to monitor that lab workers aren’t exposed to too much radiation. Such a device that detects this should have an energy harvester so that batteries aren’t required. The need for an energy harvester that generates power from a user’s movements in 2 dimensions is needed. This energy harvester is needed to power a radiation monitor. An energy harvester that generates power based off movements in 2 dimensions was developed. The energy harvester was created through a series of prototypes. Each prototype was built from a CAD drawing and a stereolithography …

Ferroelectric Batio3/Srtio3 Multilayered Thin Films For Room-Temperature Tunable Microwave Elements, Ming Liu, Chunrui Ma, Gregory Collins, Jian Liu, Chonglin Chen, Andy D. Alemayehu, Guru Subramanyam, Ying Ding, Jianghua Chen, Chao Dai, Yuan Lin, Melanie W. Cole

Electrical and Computer Engineering Faculty Publications

Ferroelectric BaTiO3/SrTiO3 with optimized c-axis-oriented multilayered thin films were epitaxially fabricated on (001) MgO substrates. The microstructural studies indicate that the in-plane interface relationships between the films as well as the substrate are determined to be (001)SrTiO3//(001)BaTiO3//(001)MgO and [100]SrTiO3//[100]BaTiO3//[100]MgO. The microwave (5 to 18 GHz) dielectric measurements reveal that the multilayered thin films have excellent dielectric properties with large dielectric constant, low dielectric loss, and high dielectric tunability, which suggests that the as-grown ferroelectric multilayered thin films can be developed for room-temperature tunable microwave elements and related device applications.

Automated Channel Assessment For Single Chip Medradio Transceivers, Mark Alexander Hillig

Dissertations and Theses

Modern implantable and body worn medical devices leverage wireless telemetry to improve patient experience and expand therapeutic options. Wireless medical devices are subject to a unique set of regulations in which monitoring of the available frequency spectrum is a requirement. To this end, implants use software protocols to assess the in-band activity to determine which channel should be used. These software protocols take valuable processing time and possibly degrade the operational lifetime of the battery. Implantable medical devices often take advantage of a single chip transceiver as the physical layer for wireless communications. Embedding the channel assessment task in the …

Anatomical Loading On A Uwb Antenna For Shoe Toe Box, Domenico Gaetano, Patrick Mcevoy, Max Ammann, C Brannigan, Louise Keating, Frances Horgan

Conference Papers

A UWB 6.0-8.5 GHz monopole antenna for mounting on the toe­box area of footwear is designed using a detailed model of a running shoe and a foot-shaped phantom. Variation of anatomical features between individual people gives rise to different proximity and permittivity loads on the antenna. To take account of environment, the antenna design optimization considers different proximity distances for impact on the reflection coefficient and on the radiation efficiency.

Lunalight - Bringing Light To The Expanding World, Gabriela M. Igel, Daniel J. Patrick, Kimberley M. Smith

Materials Engineering

The LunaLight, a solar rechargeable light and cell phone charger, addresses the lack of access to electricity faced by 1.4 billion of the world’s population (International Finance Corporation). The LunaTech team has developed a product that is bright, simple, compact, versatile and competitive with existing products. Through a partnership with the non-profit organization One Million Lights, LunaTech has improved a previous team’s design to address user feedback, concerns of durability, and manufacturability.

The LunaLight design includes a 5 component plastic housing held together by 4 screws, a surface mounted PCB, a lithium-ion (Li-Ion) battery, one high-brightness LED, a solar panel, …

Characterization And Modeling Of An O-Band 1310 Nm Sampled-Grating Distributed Bragg Reflector (Sg-Dbr) Laser For Optical Coherence Tomography (Oct) Applications, Desmond Charles Talkington

Master's Theses

In this project, the performance aspects of a new early generation 1310 nm Sampled-Grating Distributed Bragg Reflector (SG-DBR) semiconductor laser are investigated. SG-DBR lasers are ideal for Source Swept Optical Coherence Tomography (SS-OCT), a Fourier-Domain based approach for OCT, necessitating a tunable wavelength source. Three internal sections control the frequency output for tuning, along with two amplifiers for amplitude control. These O-band SG-DBR devices are now being produced in research quantities. SG-DBR lasers have been produced at 1550 and 1600 nm for some times. Fundamental questions regarding the performance of the 1310 nm devices must be quantified. Standard metrics including …

Fpga Hardware Accelerators - Case Study On Design Methodologies And Trade-Offs, Matthew V. Ryan

Theses

Previous research has shown that the performance of any computation is directly related to the architecture on which it is performed. As a result, the performance of compute intensive applications can be improved using heterogeneous systems. These systems consist of various processor architectures such as CPU, FPGA, DSP, and GPU. Individual computations can be performed in parallel on different processor architecrues within the heterogeneous system. Computations are performed by utilizing existing designs from implementation libraries. There is a lack of FPGA accelerators for use in these libraries and as such additional implementations need to be designed.

Different design methodologies for …

Spice Netlist Generation For Electrical Parasitic Modeling Of Multi-Chip Power Module Designs, Peter Tucker

Electrical Engineering Undergraduate Honors Theses

Multi-Chip Power Module (MCPM) designs are widely used in the area of power electronics to control multiple power semiconductor devices in a single package. The work described in this thesis is part of a larger ongoing project aimed at designing and implementing a computer aided drafting tool to assist in analysis and optimization of MCPM designs. This thesis work adds to the software tool the ability to export an electrical parasitic model of a power module layout into a SPICE format that can be run through an external SPICE circuit simulator. The code was implemented in python using NetworkX graphs …

Device Characterization And Compact Modeling Of The Sige Hbt In Extreme Temperature Environments, Beth Olivia Woods

Graduate Theses and Dissertations

The silicon germanium heterojunction bipolar transistor, SiGe HBT, has very high frequency response but limited voltage range. Commercial communication applications in wireless and system integration have driven the development of the SiGe HBT. However, the device's excellent electrical performance goes beyond the commercial environment. The SiGe HBT performs exceptionally at low temperatures. The device DC current gain and AC small-signal gain significantly increase in the cryogenic temperature range. Applications at low temperatures with expansive temperature range specifications need an HBT compact model to accurately represent the device's performance.

In this work, a compact model referenced at 300K was developed to …

Iii-V Bismide Optoelectronic Devices, Dongsheng Fan

Graduate Theses and Dissertations

This dissertation explores modeling, molecular beam epitaxy growth, and fabrication of III-V bismide optoelectronic devices, which are of great importance in modern applications of telecommunication, gas sensing, environment monitoring, etc. In the current room-temperature continuous-wave operational GaSb-based type-I InGaAsSb/AlGaInAsSb quantum well laser diodes in 3-4 um mid-wavelength range, the lasing wavelength and performance of the devices are limited due to the lack of hole confinement in the active regions. In this dissertation, a novel GaSb-based GaInAsSbBi material is proposed to replace the conventional InGaAsSb material in the quantum well region, which enables the laser diodes achieve up to 4 µm …

Novel Test Fixture For Characterizing Microcontacts: Performance And Reliability, Benjamin F. Toler

Theses and Dissertations

Engineers have attempted to improve reliability and lifecycle performance using novel micro-contact metals, unique mechanical designs and packaging. Contact resistance can evolve over the lifetime of the micro-switch by increasing until failure. This work shows the fabrication of micro-contact support structures and test fixture which allow for micro-contact testing, with an emphasis on the fixture's design to allow the determination and analysis of the appropriate failure mode. The other effort of this investigation is the development of a micro-contact test fixture which can measure contact force and resistance directly and perform initial micro-contact characterization, and two forms of lifecycle testing …

Digitally Programmable Rf Mems Filters With Mechanically Coupled Resonators, Hengky Chandrahalim, Sunil Ashok Bhave

AFIT Patents

A digitally-tunable RF MEMS filter includes a substrate and a plurality of mechanically coupled resonators, wherein a first and a last resonator of the plurality of mechanically coupled resonators are configured to be electrostatically transduced. One or more of the plurality of mechanically coupled resonators are configured to be biased relative to the substrate such that the one or more biased resonators may be brought substantially in contact with the substrate. In a method of digitally tuning an RF MEMS filter having a mechanically coupled resonator array, a DC bias voltage is applied to at least a first resonator and …

Dc, Rf, And Thermal Characterization Of High Electric Field Induced Degradation Mechanisms In Gan-On-Si High Electron Mobility Transistors, Matthew Anthony Bloom

Master's Theses

Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are becoming increasingly popular in power amplifier systems as an alternative to bulkier vacuum tube technologies. GaN offers advantages over other III-V semiconductor heterostructures such as a large bandgap energy, a low dielectric constant, and a high critical breakdown field. The aforementioned qualities make GaN a prime candidate for high-power and radiation-hardened applications using a smaller form-factor. Several different types of semiconductor substrates have been considered for their thermal properties and cost-effectiveness, and Silicon (Si) has been of increasing interest due to a balance between both factors.

In this thesis, the DC, …

A 40 Ghz Power Amplifier Using A Low Cost High Volume 0.15 Um Optical Lithography Phemt Process, Kenneth W. Mays

Dissertations and Theses

The demand for higher frequency applications is largely driven by bandwidth. The evolution of circuits in the microwave and millimeter frequency ranges always demands higher performance and lower cost as the technology and specification requirements evolve. Thus the development of new processes addressing higher frequencies and bandwidth requirements is essential to the growth of any semiconductor company participating in these markets. There exist processes which can perform in the higher frequency design space from a technical perspective. However, a cost effective solution must complement the technical merits for deployment. Thus a new 0.15 um optical lithography pHEMT process was developed …

Extending Device Performance In Photonic Devices Using Piezoelectric Properties, Gregory Edward Triplett

Electrical and Computer Engineering Publications

This study focuses on the influence of epi-layer strain and piezoelectric effects in asymmetric GaInAs/GaAlAs action regions that potentially lead to intra-cavity frequency mixing. The theoretical limits for conduction and valence band offsets in lattice-matched semiconductor structures have resulted in the deployment of non-traditional approaches such as strain compensation to extend wavelength in intersubband devices, where strain limits are related to misfit dislocation generation. Strain and piezoelectric effects have been studied and verified using select photonic device designs. Metrics under this effort also included dipole strength, oscillator strength, and offset of energy transitions, which are strongly correlated with induced piezoelectric …

Pseudomorphic Growth Of Inas On Misoriented Gaas For Extending Quantum Cascade Laser Wavelength, Gregory Edward Triplett, Charles Meyer, Emily Cheng, Justin Grayer, David Mueller, Denzil Roberts, Samuel Graham

Electrical and Computer Engineering Publications

The authors have studied the impact of epilayer strain on the deposition of InAs/GaAs on (100) and (111)B with 2 degrees offset toward 2-1-1 surfaces. Consequences of a 7% lattice mismatch between these orientations in the form of three-dimensional growth are less apparent for (111)B with 2 degrees offset toward 2-1-1 surfaces compared to (100). By exploring a range of molecular beam epitaxy process parameters for InAs/GaAs growth and utilizing scanning electron microscopy, atomic force microscopy, and Raman spectroscopy to evaluate the quality of these strained layers, the authors develop empirical models that describe the influence of the process conditions …

Materials Selection And Processing Techniques For Small Spacecraft Solar Cell Arrays, Naseem M. Torabi

Theses and Dissertations--Electrical and Computer Engineering

Body mounted germanium substrate solar cell arrays form the faces of many small satellite designs to provide the primary power source on orbit. High efficiency solar cells are made affordable for university satellite programs as triangular devices trimmed from wafer scale solar cells. The smaller cells allow array designs to pack tightly around antenna mounts and payload instruments, giving the board design flexibility. One objective of this work is to investigate the reliability of solar cells attached to FR-4 printed circuit boards. FR-4 circuit boards have significantly higher thermal expansion coefficients and lower thermal conductivities than germanium. This thermal expansion …

Wireless Sensor Networks And The Internet Of Things, Yingtao Jiang, Lei Zhang, Ling Wang

Electrical & Computer Engineering Faculty Research

It is estimated that mobile internet devices that can act as sensors will outnumber humans this year (2013), and by 2015, there will be about 15 billion internet-connected devices. Related applications are thriving in commercial, civic, and scientific operations that involve sensors, web, and services, leading by both academic societies and industry companies. It is commonly accepted that the next generation of internet is becoming the “Internet of Things (IoT)” which is a worldwide network of interconnected objects and their virtual representations uniquely addressable based on standard communication protocols. Identified by a unique address, any object including computers, mobile phones, …

Study Of N Incorporation In Insb On Gaas By Molecular Beam Epitaxy For Long Wavelength Infrared Devices, Nimai Chand Patra

Dissertations

The distinguishing features of dilute nitride III-V semiconductors lie in the large simultaneous reduction in the band gap and lattice parameter when N is incorporated in small amounts in an otherwise wide band gap III-V material. In particular, N incorporation in InSb is attracting great attention due to its potential applications in the long wavelength infrared (LWIR) applications. However, the relatively small atomic size of N with respect to Sb makes the growth of good quality InSbN layers challenging with effective N incorporation. In this dissertation we present a correlation of the molecular beam epitaxial growth parameters on the type …