Engineering Commons^™

Programmable Microstrip Dipole Antenna Design, Jing Zhu

Theses

The narrow bandwidth of microstrip dipole antennas is a major limitation for many applications. A method to increase the microstrip dipole antenna bandwidth is illustrated in this thesis. The proposed method utilizes micromechanical actuators to adjust the electrical length of the dipole antenna. The length change is realized by the activities of several microactuators arranged on both arms of the antenna. The radiation pattern and input impedance, as well as the microactuator mechanisms are detailed in this thesis. A programmable microstrip dipole antenna including the microactuators has been designed with the feedline taken into consideration. The fabrication techniques for this …

A Current-Mode Fdnr Circuit Element Using Capacitive Gyrators, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A current-mode implementation of a frequency-dependent negative resistance (FDNR) element is presented using a novel capacitive gyrator. This FDNR element lends itself well to the design of low-pass ladder filters and its use will result in a more efficient integrated circuit implementation than filters that simulate floating inductors using resistive gyrators.

The Evaluation Of Device Model Dependence In The Design Of A High-Frequency, Analog, Cmos Transconductance-C Filter, Susan Rose Brotman

Dissertations and Theses

It is important to have the ability to predict the effects of device model variation when designing integrated transconductance-C type active filters. Applying these filters to integrated circuit design has become increasingly popular due to its ease of implementation in monolithic form. With the introduction of fully automated design tools, predictable behavior of high-level variables becomes still more important. The purpose of this study is to evaluate the process parameter spread of analog device models to determine the effect on the design parameters of an active filter. This information's significant contribution directly effects the feasibility and realization of automating analog …

High-Frequency Analog Voltage Converter Design, Ping Xu

Dissertations and Theses

For many high-speed, high-performance circuits, purely differential inputs are needed. This project focuses on building high-speed voltage converters which can transfer a single-ended signal to a purely differential signal, or a differential input signal to a single-ended signal.

Operational transconductance amplifier (OTAs) techniques are widely used in high-speed continuous-time integrated analog signal processing (ASP) circuits because resistors, inductors, integrators, buffers, multipliers and filters can be built by OTAs and capacitors. Taking advantage of OTAs, very-high-speed voltage converters are designed in CMOS technology. These converters can work in a frequency range from DC (0Hz) up to 100MHz and higher, and keep …

The Effects Of Channel Curvature And Protusion Height On Nucleate Boiling And The Critical Heat Flux Of A Simulated Electronic Chip, John E. Leland

Office for Research Publications and Presentations

The quest for higher power yet smaller electronics has given rise to the need for very effective cooling of these electronics. Because one of the foremost problems in electronics cooling is achieving high heat flux cooling within small packages while expending minimal pumping power, one focus of this study was to investigate the effects of channel curvature on the CHF. Experimental data were obtained for flow rates of 1-7 m/s, subcoolings of 5-35"C, and radii of curvature of 25.4 and 50.8 mm. A correlation was obtained for these data which provided an excellent fit.

One condition that has been ignored …

Electrical And Crystallographic Characterization Of Cdte Grown By The Vapor Transport Method, Jack L. Boone, Gene Cantwell, W. C. Harsch, J. E. Thomas, B. A. Foreman

Electrical and Computer Engineering Faculty Research & Creative Works

Crystallographic and electrical characterization techniques were performed on CdTe single crystal samples grown by the sublimation and physical vapor transport (SPVT) technique. The SPVT growth process described here has resulted in the routine growth of 45-50 mm diameter, 250-300 g boules of single crystal CdTe. As-grown material is p-type in the 5-10 ω cm range. Etch pit densities (EPD) are nominally 7x104 cm-2 along the [111] growth direction and 3x104 cm-2 along the [111] direction. X-ray full width at half maximum (FWHM) on recent samples is 8.6 arc sec compared to 8.5 arc sec theoretical. The as-grown p-type material displays …

Advanced Navigation For Planetary Vehicles Applying An Approximate Mapping Technique, Timothy R. Mcjunkin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis provides a method for compressing the information provided by JPL Mars rover obstacle sensors by creating an approximate map of the terrain around the vehicle. This thesis demonstrates that this method provides adequate information for a human operator to negotiate complex obstacles fields.

By dividing the area around the vehicle into regions and classifying each region as to how dangerous (impassable), the sensor data can be accumulated with minimal overhead. The terrain in each region has a number between zero and one, with zero meaning completely passable and one meaning completely impassable. A continuum of possible values between …

Multirate Time-Frequency Distributions, John R. O'Hair

Theses and Dissertations

Multirate systems, which find application in the design and analysis of filter banks, are demonstrated to also be useful as a computational paradigm. It is shown that any problem which can be expressed a set of vector-vector, matrix-vector or matrix-matrix operations can be recast using multirate. This means all of numerical linear algebra can be recast using multirate as the underlying computational paradigm. As a non-trivial example, the multirate computational paradigm is applied to the problem of Generalized Discrete Time- Frequency Distributions GDTFD to create a new family of fast algorithms. The first of this new class of distributions is …

Constraint Objects, Divesh Srivastava, Raghu Ramakrishnan, Peter Revesz

School of Computing: Conference and Workshop Papers

We describe the Constraint Object Data Model (CODM), which enhances an object-based data model with existential constraints to naturally represent partially specified information. We present the Constraint Object Query Language (COQL), a declarative, rule-based query language that can be used to infer relationships about and monotonically refine information represented in the CODM. COQL has a model-theoretic and an equivalent fixed-point semantics, based on the notions of constraint entailment and "proofs in all possible worlds." We also provide a novel polynomial-time algorithm for quantifier elimination for set-order constraints, a restricted class of set constraints that uses membership of subset-equal.

The Design Of An Augmentative Communications Device, Darren Blaser, Scott Sorenson

Undergraduate Honors Capstone Projects

There is an extremely large number of people in the modem world who have difficulty communicating. Among these are approximately 25 million people with cerebral palsy. Cerebral palsy is a disability that is usually caused during, or shortly after birth. Cerebral palsy usually affects a person's motor skills and sense of balance, often rendering them incapable of speaking clearly enough to be understood well. Because this group of people cannot communicate as effectively as other individuals, many uninformed people suppose they do not have as great a need to speak, to say things like, "How are you?", ''I'm Hungry", "Thank …

Fluttering Fountains: Stability Criteria, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The fluttering oscillations that have long been seen in falling sheets of water have recently been subjected to detailed theoretical analysis. In this study stability criteria for these oscillations are derived and discussed. These criteria provide insight into the physical mechanisms of the instability and may be employed in the design of fluttering waterfall systems.

High Resolution Liquid Crystal Phase Grating Formed By Fringing Fields From Interdigitated Electrodes, Gregory P. Nordin, M. Friends, J. M. Jarem, S. T. Kowel, J. H. Kulick, T. Leslie, R. G. Lindquist

Faculty Publications

We report the formation of thin anisotropic phase gratings in a nematic liquid-crystalline film by use of lateral (fringing) electric fields induced by transparent interdigitated electrodes. These gratings yield high diffraction efficiency (>30%) with a strong dependence on the readout beam incidence angle. In addition, the formation of a defect wall is observed that has a significant effect on the diffraction properties of the phase grating.

On Issues Of Equalization With The Decorrelation Algorithm : Fast Converging Structures And Finite-Precision, Andrew James Bateman

Theses

To increase the rate of convergence of the blind, adaptive, decision feedback equalizer based on the decorrelation criterion, structures have been proposed which dramatically increase the complexity of the equalizer. The complexity of an algorithm has a direct bearing on the cost of implementing the algorithm in either hardware or software. In this thesis, more computationally efficient structures, based on the fast transversal filter and lattice algorithms, are proposed for the decorrelation algorithm which maintain the high rate of convergence of the more complex algorithms. Furthermore, the performance of the decorrelation algorithm in a finite-precision environment will be studied and …

Logic Synthesis With High Testability For Cellular Arrays, Andisheh Sarabi

Dissertations and Theses

The new Field Programmable Gate Array (FPGA) technologies and their structures have opened up new approaches to logic design and synthesis. The main feature of an FPGA is an array of logic blocks surrounded by a programmable interconnection structure. Cellular FPGAs are a special class of FPGAs which are distinguished by their fine granularity and their emphasis on local cell interconnects. While these characteristics call for specialized synthesis tools, the availability of logic gates other than Boolean AND, OR and NOT in these architectures opens up new possibilities for synthesis. Among the possible realizations of Boolean functions, XOR logic is …

Plains Electric Members Service Area_04-29-1994, University Of New Mexico Bureau Of Business And Economic Research

BBER Publications

This report presents historical and projected socioeconomic data for 19 New Mexico and two Arizona counties which comprise the service areas of the distribution cooperatives in the Plains Electric Generation and Transmission Cooperative, Inc., system.

An Analysis Of The Linked-Pulse In Steady-State Free Precession In Mri, Fang Li

Dissertations and Theses

The steady-state free precession (SSFP) is one type of the fast scanning technique in MRI. So far most of its analysis are concentrated on the gradient echo SSFP (GR SSFP), very few paper discuss the spin echo SSFP (SE SSFP), and they are usually based on the simplified the hard pulse assumption. The advantage of the SE SSFP is that it can refocus the dephasing caused by the magnetic field inhomogeneity, which is the disadvantage of the GR SSFP. Also the hard pulse model can provide very limited information.

The purpose of this paper is to establish the soft pulse …

Developing A Benchmark For Evaluating The Performance Of Parallel Computers, D. Ladd Williamson

Undergraduate Honors Capstone Projects

This paper discusses the development of a portable suite of benchmarking programs for parallel computers. Comparative measurement of the performance of parallel computing systems has been limited because of the great diversity of architectures and of processor interconnection schemes. One solution is to translate benchmark codes into a consistent and portable parallel language. This paper reports on progress in developing such a portable suite of benchmarks. An extensive introduction to parallel computing is included as an appendix, to provide a thorough understanding of the factors complicating development of the performance suite. Key to the development was the use of p4, …

Donor Complex Formation Due To A High-Dose Ge Implant Into Si, Ashawant Gupta, M. Mahmudur Rahman, Jianmin Qiao, Cary Y. Yang

Electrical and Computer Engineering

To investigate boron deactivation and/or donor complex formation due to a high‐dose Ge and C implantation and the subsequent solid phase epitaxy, SiGe and SiGeC layers were fabricated and characterized. Cross‐sectional transmission electron microscopy indicated that the SiGe layer with a peak Ge concentration of 5 at. % was strained; whereas, for higher concentrations, stacking faults were observed from the surface to the projected range of the Ge as a result of strain relaxation. Photoluminescence (PL) results were found to be consistent with dopant deactivation due to Ge implantation and the subsequent solid phase epitaxial growth of the amorphous layer. …

Performance Evaluation Tools For Interconnection Network Design, Anna Kolinska

Dissertations and Theses

A methodology is proposed for designing performance optimized computer systems. The methodology uses software tools created for performance monitoring and evaluation of parallel programs, replacing actual hardware with a simulator modeling the hardware under development. We claim that a software environment can help hardware designers to make decisions on the architectural design level. A simulator executes real programs and provides access to performance monitors from user's code. The performance monitoring system collects data traces when running the simulator and the performance analysis module extracts performance data of interest, that are later displayed with visualization tools. Key features of our methodology …

Interferometric Determination Of The Quadratic Electro-Optic Coefficient Of Nitrobenzene, Harshad P. Sardesai, William C. Nunnally, P. F. Williams

P. F. (Paul Frazer) Williams Publications

An interferometric method that was used to measure the electro-optic s₁₁ coefficient of nitrobenzene is presented. The method uses a Mach-Zehnder interferometer arrangement that produces a finite fringe interferogram. A nitrobenzene Kerr cell is placed in one arm of the interferometer and a pulsed high voltage is applied to the two rectangular electrodes. The voltage application causes the fringe image to shift in time, and this fringe shift is measured by a streak camera that streaks the fringe image across a slit. The streak start time is chosen before the application of the voltage pulse and ends after the …

A State Architecture Notation Specification Of The Electronic Industries Association Rs-232-C Generic Interchange Circuit, Nelson E. Hastings

Masters Theses

The Electronic Industries Association (BIA) RS-232-C recommendation is an interface specification which was introduced in August 1969 and presents a natural language specification of a 25 pin binary serial data interface between a Data Communication Equipment (DCE) and a Data Terminal Equipment (DTE). The exchange of data signals between a DCE and a DTE ultimately provides the means for DTEs to communicate on networks of DCEs interconnected by different transmission mediums possibly over great distances. The exchange of data signals between a DCE and a DTE occurs at an interface via interchange circuits.

In this thesis we will create a …

Diamond Thin Film Sensors For Hypersonic Flow Studies, Bhaskar Kumar Bulusu

Electrical & Computer Engineering Theses & Dissertations

Conventional metal film sensors can measure flow instabilities of the order of 60 kHz. The turbulence fluctuations in the hypersonic regime are of the order of 200- 400 kHz. To measure these fluctuations, sensors with an enhanced frequency response are required. Therefore, it is required to identify the parameters to enhance the frequency response. These include parameters such as the temperature sensitivity, the resistivity, the thermal conductivity, the diffusivity, specific heat capacity and the geometric size and shape of the film and the substrate. A selection of materials was then carried out to maximize the frequency response. Diamond was identified …

Derivative Absorption Spectroscopy With Tunable Laser Diodes, Andrew D. Jackson

Electrical & Computer Engineering Theses & Dissertations

Derivative Absorption Spectroscopy using tunable diode lasers provides a non­ intrusive, sensitive, and convenient method for monitoring gaseous characteristics such as concentration, temperature, and flow velocity. In addition, the specie type can be identified, and if the equation of state is known, pressure may be deduced.

This technique was used on molecular oxygen, in which the rovibronic transitions of the A-band ( b ¹ ∑_g ⁺ ← X ³ ∑g ^- ; v^II = O, v^I = O) were probed. Phase sensitive detection with a lock-in amplifier provides the flexibility to examine lineshape derivatives; several such derivative …

Dynamic Task Scheduling For The Atamm Multicomputer Operating System Using Embedded Firmware On Microcontrollers, Sudhir Sastry

Electrical & Computer Engineering Theses & Dissertations

A dynamic task scheduling strategy for the distributed processing of large grain dataflow algorithms using embedded firmware on an ATAMM testbed consisting of interconnected microcontrollers is presented in this thesis. The ODU/NASA developed Algorithm to Architecture Mapping Model, ATAMM, uses marked graph models to specify data and control flow for the execution of iterative, deterministic large grain dataflow algorithms in a multicomputing environment. The testbed consists of a bank of four 68HC11 microcontrollers that communicate over a token bus. The token bus arbitration scheme used is contention free and well suited for real-time computing applications. The execution of data flow …

Characterization Of Electromagnetically Coupled Superquadric Loop Antennas For Mobile Communications Applications, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

Analysis of two mutually coupled loop antennas with arbitrary relative orientation and position and possibly different geometries is presented. The antennas are represented by generalised superquadric curves, which include circular, elliptical, and rectangular loop geometries, and they may be located either in a homogeneous region or next to an infinite ground plane. A Galerkin-type moment method with piecewise sinusoidal subsectional basis and weighting functions is used. Special consideration is given to implement the solution using curved wire segments instead of the commonly employed linear segments to improve computational efficiency. This very general computational tool is used to investigate the behaviour …

A Powerful And Computationally Efficient Algorithm For Transmission Loss Calculation, Anoop Nanda, David V. Uy, J. Nanda, E. Khan, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper deals with the formulation of transmission loss P_L of a power system through a set of new coefficients (A coefficients) which are extremely efficient, exact and robust and suitable for real time application. Results on a few IEEE test systems are exciting and encouraging. They demonstrate that these A coefficients faithfully represent the system loss, are extremely robust and need not be re-evaluated for changes in the system loading conditions either for evaluation of system loss or cost of generation for economic load dispatch.

Basic Resonant Topologies For Switching Power Supplies, Zacharias K. Vachaparambil

Department of Electrical and Computer Engineering Technical Reports

The objective of this thesis is to study the basic resonant converter topologies for switching power supplies and to compare their performance under different operating conditions. The series and parallel resonant converters are analyzed in detail. The analysis uses the state plane method, which gives a good insight of the operation of the converter. It is found that these converters have more desirable characteristics when operated at a frequency above the resonant frequency rather than below it. Analytical results are verified by sinlulation and experiment.

Optimization Of Electron-Beam Activated Gaas Switches, Raymond Jack Allen Iii

Electrical & Computer Engineering Theses & Dissertations

The use of electron induced luminescence (cathodoluminescence) in gallium arsenide offers the possibility to modulate the conductance of the material on a timescale of nanoseconds and with a pulse rate of MHz, through modulation of an electron-beam current. This ionization mechanism allows the utilization of semi-insulating GaAs in fast, high power closing and opening switches. The efficiency of the switches is determined by the hold-off voltage of the GaAs switches, and by the conversion efficiency of electron energy into (useful) photon energy. Studies of the dark-current and the electron-beam induced conductance in semi-insulating GaAs have been performed in order to …

Determination Of Density Of Trap States At Y2O3-Stabilized Zro2/Si Interface Of Yba2Cu3O7-Δ/Y2O3-Stabilized Zro2/Si Capacitors, Jianmin Qiao, Kuohsu Wang, Cary Y. Yang

Electrical and Computer Engineering

Yba₂Cu₃O_7-δ/yttria‐stabilized zirconia (YSZ)/silicon superconductor‐insulator‐semiconductor capacitors are characterized with current‐voltage and capacitance‐voltage (C‐V) measurements at different temperatures between 223 and 80 K. As a result of ‘‘freezing’’ of mobile ions in YSZ, effects of trapped charge at the YSZ/Si interface dominate the device electrical properties at superconducting temperatures. Density of interface states and its temperature dependence are determined using a modified high frequency C‐V method, in which the temperature dependences of band gap, Fermi level, and active dopant and intrinsic carrier concentrations are considered. At superconducting temperatures, e.g., 80 K, the interface state density within …

An Artifically Intelligent Word Recognizer To Control Appliances And Switches: The Home That Listens To Your Every Command, Joseph Bauer, Rick Steurer

Opportunities for Undergraduate Research Experience Program (OURE)

The most natural and informal means of communication and control is speech communication. Therefore, it also goes to say that control of home appliances, stereo, computer, and heating thermostat to name a few will naturally tend to this form of control.

A word recognition home controller was designed, constructed, and tested successfully. This paper will discuss the low-cost overall design, implementation, and results of a presently constructed and working "home controller." The results of this successful project in voice control are very promising and agree with the original hypothesis: A home that listens to your command is very much a …