Engineering Commons^™

Resonant Antennas Based On Coupled Transmission-Line Metamaterials, Christopher S. Merola

Masters Theses 1911 - February 2014

A novel microstrip patch antenna topology is presented for achieving a dual-band response with arbitrarily closely spaced resonances. This topology is based on a coupled transmission line structure in order to take advantage of the separation in propagation constants for parallel (even-mode) and anti-parallel (odd-mode) current modes. Applying a metamaterials inspired design approach, periodic reactive load­ings are used to design the underlying transmission line to have specific propagation constants necessary to realize a desired separation between two resonant frequencies. Using a single probe feed for a finite coupled line segment, both even-and odd-mode resonances can be excited to radiate efficiently …

Electromagnetic Modeling Of Photolithography Aerial Image Formation Using The Octree Finite Element Method, Seth A. Jackson

Masters Theses 1911 - February 2014

Modern semiconductor manufacturing requires photolithographic printing of subillumination wavelength features in photoresist via electromagnetic energy scattered by complicated photomask designs. This results in aerial images which are subject to constructive and destructive wave interference, as well as electromagnetic resonances in the photomask features. This thesis proposes a 3-D full-wave frequency domain nonconformal Octree mesh based Finite Element Method (OFEM) electromagnetic scattering solver in combination with Fourier Optics to accurately simulate the entire projection photolithography system, from illumination source to final image intensity in the photoresist layer. A rapid 1-irregular octree based geometry model mesher is developed and shown to perform …

Approaches To Multiprocessor Error Recovery Using An On-Chip Interconnect Subsystem, Ramakrishna P. Vadlamani

Masters Theses 1911 - February 2014

For future multicores, a dedicated interconnect subsystem for on-chip monitors was found to be highly beneficial in terms of scalability, performance and area. In this thesis, such a monitor network (MNoC) is used for multicores to support selective error identification and recovery and maintain target chip reliability in the context of dynamic voltage and frequency scaling (DVFS). A selective shared memory multiprocessor recovery is performed using MNoC in which, when an error is detected, only the group of processors sharing an application with the affected processors are recovered. Although the use of DVFS in contemporary multicores provides significant protection from …

Calibration Of The Umass Advanced Multi-Frequency Radar, Matthew Mclinden

Masters Theses 1911 - February 2014

The Advanced Multi-Frequency Radar is a three-frequency system designed and built by the University of Massachusetts Microwave Remote Sensing Lab (MIRSL). The radar has three frequencies, Ku-band (13.4 GHz), Ka-band (35.6 GHz), and W-band (94.92GHz). The additional information gained from additional frequencies allows the system to be sensitive to a wide range of atmospheric and precipitation particle sizes, while increasing the ability to derive particle microphysics from radar retrievals.

This thesis details the calibration of data from the Canadian CloudSat/CALIPSO Validation Project (C3VP) held during January 2007 in Ontario, Canada. The calibration used internal calibration path data and was confirmed …

Scalable, Memory-Intensive Scientific Computing On Field Programmable Gate Arrays, Salma Mirza

Masters Theses 1911 - February 2014

Cache-based, general purpose CPUs perform at a small fraction of their maximum floating point performance when executing memory-intensive simulations, such as those required for many scientific computing problems. This is due to the memory bottleneck that is encountered with large arrays that must be stored in dynamic RAM. A system of FPGAs, with a large enough memory bandwidth, and clocked at only hundreds of MHz can outperform a CPU clocked at GHz in terms of floating point performance. An FPGA core designed for a target performance that does not unnecessarily exceed the memory imposed bottleneck can then be distributed, along …

Fast Parameter-Space Sweep Of Wideband Electromagnetic Systems Using Bt-Pod, Wei Wang

Masters Theses 1911 - February 2014

Modeling and design of high frequency electronic systems such as antennas and microwave devices require the rigorous numerical solution of Maxwell’s equa- tions. The frequency-domain (time-harmonic) tangential vector finite element method (TVFEM) for Maxwell equations results in a second-order dynamical electromagnetic model that must be repeatedly solved for multiple frequencies, excitation or material parameters each design loop. This leads to extremely long design turnaround that often is not optimal. This work will propose an accurate, error controllable and ef- ficient multi-parametric model order reduction scheme that significantly accelerate these parameters sweep. At the core of this work is the proper …

Optical Lithography Simulation Using Wavelet Transform, Rance Rodrigues

Masters Theses 1911 - February 2014

Optical lithography is an indispensible step in the process flow of Design for Manufacturability (DFM). Optical lithography simulation is a compute intensive task and simulation performance, or lack thereof can be a determining factor in time to market. Thus, the efficiency of lithography simulation is of paramount importance. Coherent decomposition is a popular simulation technique for aerial imaging simulation. In this thesis, we propose an approximate simulation technique based on the 2D wavelet transform and use a number of optimization methods to further improve polygon edge detection. Results show that the proposed method suffers from an average error of less …

Efficient Modeling Techniques For Time-Dependent Quantum System With Applications To Carbon Nanotubes, Zuojing Chen

Masters Theses 1911 - February 2014

The famous Moore's law states: Since the invention of the integrated circuit, the number of transistors that can be placed on an integrated circuit has increased exponentially, doubling approximately every two years. As a result of the downscaling of the size of the transistor, quantum effects have become increasingly important while affecting significantly the device performances. Nowadays, at the nanometer scale, inter-atomic interactions and quantum mechanical properties need to be studied extensively. Device and material simulations are important to achieve these goals because they are flexible and less expensive than experiments. They are also important for designing and characterizing new …

Data Fusion For The Problem Of Protein Sidechain Assignment, Yang Lei

Masters Theses 1911 - February 2014

In this thesis, we study the problem of protein side chain assignment (SCA) given

multiple sources of experimental and modeling data. In particular, the mechanism

of X-ray crystallography (X-ray) is re-examined using Fourier analysis, and a novel

probabilistic model of X-ray is proposed for SCA's decision making. The relationship

between the measurements in X-ray and the desired structure is reformulated in terms

of Discrete Fourier Transform (DFT). The decision making is performed by developing

a new resolution-dependent electron density map (EDM) model and applying

Maximum Likelihood (ML) estimation, which simply reduces to the Least Squares

(LS) solution. Calculation of the …

Terahertz And Microwave Detection Using Metallic Single Wall Carbon Nanotubes, Enrique A. Carrion

Masters Theses 1911 - February 2014

Carbon nanotubes (CNTs) are promising nanomaterials for high frequency applications due to their unique physical characteristics. CNTs have a low heat capacity, low intrinsic capacitance, and incredibly fast thermal time constants. They can also exhibit ballistic transport at low bias, for both phonons and electrons, as evident by their fairly long mean free paths. However, despite the great potential they present, the RF behavior of these nanostructures is not completely understood. In order to explore this high frequency regime we studied the microwave (MW) and terahertz (THz) response of individual and bundled single wall nanotube based devices. This thesis is …

Application Specific Customization And Scalability Of Soft Multiprocessors, Deepak C. Unnikrishnan

Masters Theses 1911 - February 2014

Soft multiprocessor systems exploit the plentiful computational resources available in field programmable devices. By virtue of their adaptability and ability to support coarse grained parallelism, they serve as excellent platforms for rapid prototyping and design space exploration of embedded multiprocessor applications. As complex applications emerge, careful mapping, processor and interconnect customization are critical to the overall performance of the multiprocessor system. In this thesis, we have developed an automated scalable framework to efficiently map applications written in a high-level programmer-friendly language to customizable soft-cores. The framework allows the user to specify the application in a high-level language called Streamit. After …

Implementation Of Network Services Supporting Multi-Party Policies, Santosh C. Proddatoori

Masters Theses 1911 - February 2014

Next-generation network architectures support complex services in the data-path of routers. A key challenge is the integration of multiple policy constraints from senders, receivers, and network providers when using such services. We introduce a multi-party service specification framework based on our “service socket” API. We illustrate the operation of this approach in an IPTV scenario that uses a video transcoding service implemented on a Cisco ISR platform.

An Uhf Frequency-Modulated Continuous Wave Wind Profiler - Development And Initial Results, Iva S. Kostadinova

Masters Theses 1911 - February 2014

The following work represents the research attempt of Dr. Frasier's group to develop a FMCW wind profiler for atmospheric boundary layer studies. The hardware development and integration are described in detail.

Information Theoretic Identification And Compensation Of Nonlinear Devices, Sepideh Dolatshahi

Masters Theses 1911 - February 2014

Breaking the anonymity of different wireless users with the purpose of decreasing internet crime rates is addressed in this thesis by considering radiometric identification techniques.

Minute imperfections and non-idealities in the different transmitter components, especially the inherent nonlinearity in power amplifiers, result in variations in their Volterra series representations which could be utilized as a signature.

For a two user scenario, signal processing algorithms based on generalized likelihood ratio test(GLRT) and the classical likelihood ratio test are introduced and the resulting receiver decision rules and performance curves are presented. These algorithms consider the high signal to noise ratio(SNR) case where …

Reliability Assessment Of A Power Grid With Customer Operated Chp Systems Using Monte Carlo Simulation, Lokesh Prakash Manohar

Masters Theses 1911 - February 2014

This thesis presents a method for reliability assessment of a power grid with distributed generation providing support to the system. The distributed generation units considered for this assessment are Combined Heat and Power (CHP) units operated by individual customers at their site. CHP refers to the simultaneous generation of useful electric and thermal energy. CHP systems have received more attention recently due to their high overall efficiency combined with decrease in costs and increase in reliability. A composite system adequacy assessment, which includes the two main components of the power grid viz., Generation and Distribution, is done using Monte Carlo …

System Performance Of Absolute Quartz-Crystal Barometers With Sub-Microbar Precision, Ganesh Kumar Subramanian Ananthanarayanan

Masters Theses 1911 - February 2014

In this thesis, the performance of absolute quartz-crystal barometers is presented, and their ability to measure, with sub-microbar precision, atmospheric pressure fluctuations with periods as short as a few seconds is demonstrated. The first observations of ocean-generated atmospheric infrasound with periods of about 5 s and sub-microbar amplitudes, called microbaroms, using single absolute barometers are presented. These barometers can measure microbaroms with amplitudes down to 50 nanobars and the 1-h estimates of microbarom amplitudes calculated from data collected independently with three collocated barometers differed by only a few nanobars. The observed microbaroms have amplitudes between 0.2 microbars and 1 microbar …

Design And Development Of A Ka-Band Interferometer For Cryospheric Applications, Harish K. Vedantham

Masters Theses 1911 - February 2014

Topographic maps of the earth are essential to geographic and earth science studies. In particular, mapping and estimating physical parameters of the earth’s water and ice cover are critical to global climate studies. Among these, snow, ocean and fresh water topography, snow wetness and water equivalent are of immediate interest to the scientific community.

Challenges in the instrument development and deployment posed by these required measurements are twofold. Firstly, these measurements are required to have global coverage, yet maintain stringent spatial resolution and accuracy margins. Secondly, snow topography measurement requires minimal electromagnetic wave penetration through snow, hence requiring the use …

Development Of A Solid-State Doppler Marine Radar, Gita P. Pathak

Masters Theses 1911 - February 2014

No abstract provided.

Miniaturization Of Microstrip Patch Antennas For Gps Applications, Steven S. Holland

Masters Theses 1911 - February 2014

The desire to incorporate multiple frequency bands of operation into personal communication devices has led to much research on reducing the size of antennas while maintaining adequate performance. GPS is one such application, where dual frequency operation, bandwidth and circular polarization pose major challenges when using traditional miniaturization techniques. Various loading methods have been studied to reduce the resonant frequency of the antenna – high permittivity dielectric loading, slot loading and cavity loading – while examining their effects on bandwidth and gain. The objective of this thesis is to provide guidelines on what is achievable using these miniaturization methods and …

A Process Variation Tolerant Self-Compensation Sense Amplifier Design, Aarti Choudhary

Masters Theses 1911 - February 2014

As we move under the aegis of the Moore's law, we have to deal with its darker side with problems like leakage and short channel effects. Once we go beyond 45nm regime process variations also have emerged as a significant design concern.Embedded memories uses sense amplifier for fast sensing and typically, sense amplifiers uses pair of matched transistors in a positive feedback environment. A small difference in voltage level of applied input signals to these matched transistors is amplified and the resulting logic signals are latched. Intra die variation causes mismatch between the sense transistors that should ideally be identical …

Power Amplifier Linearization Implementation Using A Field Programmable Gate Array, Abilash Menon

Masters Theses 1911 - February 2014

The emphasis on higher data rates, spectral efficiency and cost reduction has driven the field towards linear modulation techniques such as quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), wideband code division multiple access (WCDMA), and orthogonal frequency division multiplexing (OFDM). The result is a complex signal with a non-constant envelope and a high peak-to-average power ratio. This characteristic makes these signals particularly sensitive to the intrinsic nonlinearity of the RF power amplifier (PA) in the transmitter. The nonlinearity will generate intermodulation (IMD) components, also referred to as out-of-band emission or spectral re-growth, which interfere with adjacent channels. Such …

A Study Of A Reimaging System For Correcting Large-Scale Phase Errors In Reflector Antennas, Eugene F. Lauria

Masters Theses 1911 - February 2014

This thesis investigates a new approach for dealing with the adverse effects of large-scale deformations in the main reflector of large Cassegrain antennas. In this method, the incident aperture distribution is imaged onto a tertiary focal plane. This is accomplished by using an optical imaging system consisting of a lens mounted behind the Cassegrain focus of the antenna. The lens forms a real image of the product of the incident aperture distribution and the pupil function of the antenna. The pupil function describes the profile of the main reflector of the antenna. If the incident aperture distribution is a plane …