Engineering Commons^™

Reducing Switching Noise And Losses In Two-Stage Electric Power Converters, Abhijeet Prem

Student Research Symposium

Advancements in semiconductor devices are enabling the design of better electrical power converter systems. Wide Bandgap (WBG) switching devices from Silicon Carbide and Gallium Nitride can operate at high temperatures, voltages, and frequencies with faster turn-on/off periods, improving converter performance over silicon devices. However, WBG technology is still new, and the rapid switching transitions of these devices lead to issues such as voltage overshoots, ringing, and electromagnetic interference, which need to be addressed for widespread adoption. This work introduces a new control method for reshaping the switching voltages, which overcomes the disadvantages of fast transition time without increasing the system's …

The Effect Of A Ferrite-Core Relay Vs. An Air-Core Relay On The Output Power Characteristics Of A Three-Coil Wireless Power Transfer System, Jakob L. White

University Honors Theses

The purpose of this thesis is to determine the effect of using a ferrite-core relay on the output power characteristics of a three-coil, parallel-tuned, domino-resonator wireless power transfer (WPT) system in comparison to the effect of using an air-core relay in such a system. First, a general mathematical model is presented to describe both the ferrite-core-relay system and the air-core-relay system and to calculate their output power characteristics for seven different resistive loads at each of five different distance configurations between the coils. Next, experimental results are analyzed and compared to the mathematical results to confirm model accuracy. Finally, the …

A Simplified Accuracy Enhancement To The Saleh Am/Am Modeling And Linearization Of Solid-State Rf Power Amplifiers, Haider Al-Kanan, Fu Li

Electrical and Computer Engineering Faculty Publications and Presentations

The Saleh behavioral model exhibits high prediction accuracy for nonlinearity of traveling-wave tube power amplifiers (TWT-PAs). However, the accuracy of the Saleh model degrades when modeling solid-state power amplifiers (SSPAs) technology. In addition, the polynomial expansion of the Saleh model consists of only odd-order terms as analyzed in this work. This paper proposes a novel model accuracy enhancement for the Saleh amplitude-to-amplitude (AM/AM) model when applied to radio frequency (RF) SSPAs. The proposed model enhancement accounts for the second-order intermodulation distortion, which is an important nonlinearity challenge in wideband wireless communications. The proposed static AM/AM model is a three-parameter rational …

Spectrum Modeling Of Out-Of-Band Intermodulation For Dual-Band Rf Amplifiers In Ofdm Modulation, Xianzhen Yang, Siyuan Yan, Xiao Li, Qiang Wu, Fu Li

Electrical and Computer Engineering Faculty Publications and Presentations

Dual-band RF amplifiers play increasingly important roles in next-generation mobile communication systems including 5G, and the out-of-band intermodulation products are often not negligible since they generate interference to adjacent channels. In this article, following our previous modeling of cross-modulation for amplified dual-band signals, an analytical expression of out-of-band intermodulation for dual-band orthogonal frequency-division multiplexing signals is derived using the third-order intercept points IP₃. The experimental measurement results validate the proposed analytical expression.

A High Torque Density Halbach Rotor Coaxial Magnetic Gear, Ho Yin Wong, Jonathan Z. Bird, David Barnett, Wesley Williams

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents the design, analysis, and experimental testing results for a 5.67:1 Halbach rotor magnetic gearbox with a ferromagnetic back support. Using 3-D finite element analysis software the Halbach magnetic gearbox was calculated to achieve a volumetric torque density of 284N·m/L with only an active region outer diameter of 120mm. The experimental prototype obtained an active region volumetric torque density of 261.4N·m/L

Flip-Chip (Fc) And Fine-Pitch-Ball-Grid-Array (Fpbga) Underfills For Application In Aerospace Electronics—Brief Review, Ephraim Suhir, Reza Ghaffarian

Mechanical and Materials Engineering Faculty Publications and Presentations

In this review, some major aspects of the current underfill technologies for flip-chip (FC) and fine-pitch-ball-grid-array (FPBGA), including chip-size packaging (CSP), are addressed, with an emphasis on applications, such as aerospace electronics, for which high reliability level is imperative. The following aspects of the FC and FPGGA technologies are considered: attributes of the FC and FPBGA structures and technologies; underfill-induced stresses; the roles of the glass transition temperature (T_g) of the underfill materials; some major attributes of the lead-free solder systems with underfill; reliability-related issues; thermal fatigue of the underfilled solder joints; warpage-related issues; attributes of accelerated life …

Space-Angle Signal Processing Using A Modulated Scatter Array, Nasr Alkhafaji

Electrical and Computer Engineering PhD Day

A UHF signal processing technique is described in the Fourier Space-Angle domain that uses an array of scattering elements with reflection coefficients modulated at baseband. The illumination arrival angle distributes a UHF phase across the array, and the baseband modulator phase at each of the array elements determines the radiation angle of the desired scattered product. Undesired products are re-radiated in different directions. Example 1, 2 and 4 element arrays operate at 432 MHz array with 700 Hz modulation. 2 element arrays cancel one sideband, and the 4 element array cancels both the undesired sideband and 2nd order products. Reflection …

Drafting In Self-Timed Circuits, Christopher Cowan

Electrical and Computer Engineering PhD Day

Intervals between data items propagating in self-timed circuits are controlled by handshake signals rather than by a clock. The sequence of handshakes can be abstracted as the movement of “tokens”. In many self-timed designs, a trailing token will catch up with a leading token, even when it trails by thousands of gate delays. Simulations in SPICE of a simple GasP circular FIFO reveal this effect. Contrary to earlier work, we find the cause of drafting to be charge stored on an isolated node between two series transistors. This mechanism occurs in many decision gates that implement a logical AND. The …

Coaxial Magnetic Gearbox With A Flux Concentration Halbach Rotor And Consequent Pole Rotor Typology, Ho Yin Wong

Electrical and Computer Engineering PhD Day

This paper presents the performance comparison between a flux concentration and triple permanent magnet consequent pole magnetic gear rotor typology with the same 7.5:1 gear ratio. The triple permanent magnet consequent pole magnetic gear is unique in that it can create torque change through two field heterodyning pole combinations. The performance with respect to volumetric and mass torque density is considered. It is shown that the flux concentration typology can operate with a higher mass and volumetric higher torque density, even when using a low flux concentration ratio rotor.

Magnetically Geared Lead Screw, Mojtaba Bahrami Kouhshahi

Electrical and Computer Engineering PhD Day

New magnetically geared lead screw (MGLS) is proposed in this work, which relies only on magnetic loading. Therefore it can provide speed and force conversion like its mechanical counterparts, but unlike the mechanical gears, a MGLS contact-less operation enables it to operate without lubrication and it can operate with low noise, and higher efficiency. Its reliance on magnetic loading also provides overload protection. MGLS combines the concepts of two previously proposed actuators named linear magnetic gear (LMG) and magnetic lead screw (MLS). However, unlike the LMG and MLS the translator on a MGLS does not contain magnets and therefore for …

From A Locally Competitive Algorithm To Sensory Relevance Models, Walter Woods

Electrical and Computer Engineering PhD Day

This poster addresses the development of a new Machine Learning (ML) mechanism, the Sensory Relevance Model (SRM), as a means of splitting information processing tasks into two sub-tasks with more intuitive properties. Specifically, SRMs are a front-end for other ML techniques, re-mapping the input data to a similar space with significantly more sparsity, achieved through the transformation and suppression of inputs irrelevant to the task. Prior work has attempted to reveal this information for Neural Networks (NNs) either as a post-processing step via saliency maps or through a simple masking of the input achieved with a dot product (so-called ``attention'' …

On Dual-Band Amplifications Using Dual Two-Tones: Clarifications And Discussion, Siyuan Yan, Xianzhen Yang, Xiao Li, Fu Lo

Electrical and Computer Engineering Faculty Publications and Presentations

A significant development of recent research in nonlinear distortion is the expansion of the conventional two-tone test for power amplifiers to the concurrent dual-band transmitters, by Amin et al. A general framework using dual two-tones is developed, which shows that the output signal is affected not only by intermodulation (IM) products but also by cross-modulation (CM) products. In this paper, we will make a number of clarifications to Amin et al.'s paper. The effects of IM and CM in passband will be discussed, IM represents a reduction for compressive devices, and CM reflects an interference caused by the signal from …

Assembly Of A 3d Cellular Computer Using Folded E-Blocks, Shivendra Pandey, Nicholas J. Macias, Carmen Ciobanu, Changkyu Yoon, Christof Teuscher, David H. Gracias

Electrical and Computer Engineering Faculty Publications and Presentations

The assembly of integrated circuits in three dimensions (3D) provides a possible solution to address the ever-increasing demands of modern day electronic devices. It has been suggested that by using the third dimension, devices with high density, defect tolerance, short interconnects and small overall form factors could be created. However, apart from pseudo 3D architecture, such as monolithic integration, die, or wafer stacking, the creation of paradigms to integrate electronic low-complexity cellular building blocks in architecture that has tile space in all three dimensions has remained elusive. Here, we present software and hardware foundations for a truly 3D cellular computational …

Sparse Adaptive Local Machine Learning Algorithms For Sensing And Analytics, Jack Cannon

Undergraduate Research & Mentoring Program

The goal of digital image processing is to capture, transmit, and display images as efficiently as possible. Such tasks are computationally intensive because an image is digitally represented by large amounts of data. It is possible to render an image by reconstructing it with a subset of the most relevant data. One such procedure used to accomplish this task is commonly referred to as sparse coding. For our purpose, we use images of handwritten digits that are presented to an artificial neural network. The network implements Rozell's locally competitive algorithm (LCA) to generate a sparse code. This sparse code is …

A Constraint Language For Static Semantic Analysis Based On Scope Graphs, Hendrik Van Antwerpen, Pierre Néron, Andrew Tolmach, Eelco Visser, Guido Wachsmuth

Computer Science Faculty Publications and Presentations

In previous work, we introduced scope graphs as a formalism for describing program binding structure and performing name resolution in an AST-independent way. In this paper, we show how to use scope graphs to build static semantic analyzers. We use constraints extracted from the AST to specify facts about binding, typing, and initialization. We treat name and type resolution as separate building blocks, but our approach can handle language constructs—such as record field access—for which binding and typing are mutually dependent.We also refine and extend our previous scope graph theory to address practical concerns including ambiguity checking and support for …

Teaching Matlab And C Programming In First Year Electrical Engineering Courses Using A Data Acquisition Device, Phillip Wong, Branimir Pejcinovic

Electrical and Computer Engineering Faculty Publications and Presentations

Our industry partners often voice a complaint that our newly graduated electrical engineering (EE) students do not have sufficient programming skills. This is not a new concern. In a traditional undergraduate EE curriculum, one or two programming courses compose the entirety of the student’s training in programming. The courses may be taught by the computer science department without significant emphasis on engineering fundamentals. While the principles of computer science may be well covered, the ability to apply the knowledge to practical engineering problems is frequently lacking. To compound the problem, teaching novices the basics of programming can be very challenging …

The Smart Clock, Cory Koehler, Addison Loda, Hannah Posey-Scholl, Isak Rask

PSU High School Innovation Challenge

Modern technology continues to change and improve constantly as people find ways to make things faster, smaller, and better - but these changes often leave the elderly behind. This year’s Innovation Challenge asked groups to focus on how to create and improve technology geared towards the aging generations. For our initial research, the Grant High School team and mentors visited an elderly care center and interviewed a few of the residents, asking what types of technology currently improve their lives, and what types of technology could potentially improve their lives.

The Problem: After the interviews, we were able to identify …

Measurement And Modeling Of Passive Surface Mount Devices On Fr4 Substrates, Rahulkumar Sadanand Koche

Dissertations and Theses

Passive components like resistors, capacitors and inductors are used in every electronic system. These are the very basic components which affect the system performance at higher frequencies and it is necessary to understand and model the behavior of these components in a very accurate manner. This work focuses on utilizing Printed Circuit Board (PCB) test boards, or fixtures, made of FR4 for characterizing Surface Mount Device (SMD) components. Agilent's Advanced Design System (ADS) microwave circuit simulation software was used for designing the microstrip transmission lines as well as for generating the layout for manufacturing of the PCB. SMD resistors, capacitors …

Material Characterization Of Zinc Oxide In Bulk And Nanowire Form At Terahertz Frequencies, Forest Emerson Kernan

Dissertations and Theses

Many new applications are being proposed and developed for use in the terahertz (THz) frequency region. Similarly, many new materials are being characterized for possible use in this area. Nanostructured forms are of particular interest since they may yield desirable properties, but they remain especially challenging to characterize. This work focuses on the characterization of zinc oxide (ZnO) in bulk and nanowire form. A method for characterizing nanostructures at THz by use of a parallel-plate waveguide (PPWG) is presented. This method is novel in that it is simple, both in theory and practice, and does not require the use of …

Memristor-Based Reservoir Computing, Manjari S. Kulkarni

Dissertations and Theses

In today's nanoscale era, scaling down to even smaller feature sizes poses a significant challenge in the device fabrication, the circuit, and the system design and integration. On the other hand, nanoscale technology has also led to novel materials and devices with unique properties. The memristor is one such emergent nanoscale device that exhibits non-linear current-voltage characteristics and has an inherent memory property, i.e., its current state depends on the past. Both the non-linear and the memory property of memristors have the potential to enable solving spatial and temporal pattern recognition tasks in radically different ways from traditional binary transistor-based …

Interview With Adam Boesel, Green Micro Gym, 2011 (Audio), Adam Boesel

All Sustainability History Project Oral Histories

Interview of Adam Boesel by Teresa Celestine at Green Micro Gym Portland, Oregon on July 29th, 2011.

The interview index is available for download.

Demodulation Of Narrowband Radio Frequency Signals By Aliasing Sampling, Chun-Ching Lin

Dissertations and Theses

The objective of this thesis is to study the demodulation of narrowband radio frequency signals by aliasing sampling in order to reduce the sampling rate. The spectrum can be recreated at the lower frequency position by aliasing sampling. However, if the sampling rate is deviated from the desired one, error will occur. The sensitivity to the frequency error of aliasing sampling is studied.

One main reason of the deviation of the sampling rate is the frequency drifting of the local oscillator. Being able to compensate the oscillator drifting errors inexpensively, automatic frequency control (AFC) loops are important at receivers. Two …

Adaptive Color Correlation Of Knots In Wood Images And Weighted-Value Product Selection Methods In A Machine Vision System, John Robert Goulding

Dissertations and Theses

The biggest obstacle to robust color image processing of wood is in developing a color model that represents all possible defect colors. When the color model is too general or too specific, defect recognition fails because too many or too few non-defect pixels match the model, respectively. Because a color image of wood contains far more clear and clear-grain colored pixels than grain-knot and knot colored pixels, it is beneficial to first statistically identify and remove the clear and clear-grain colors and to use the accumulated data to simultaneously enhance and normalize the remaining grainknot and knot colored pixels. This …

Seasonal Hidden Markov Models For Stochastic Time Series With Periodically Varying Characteristics, Arthur M. Lewis

Dissertations and Theses

Novel seasonal hidden Markov models (SHMMs) for stochastic time series with periodically varying characteristics are developed. Nonlinear interactions among SHMM parameters prevent the use of the forward-backward algorithms which are usually used to fit hidden Markov models to a data sequence. Instead, Powell's direction set method for optimizing a function is repeatedly applied to adjust SHMM parameters to fit a data sequence. SHMMs are applied to a set of meteorological data consisting of 9 years of daily rain gauge readings from four sites. The fitted models capture both the annual patterns and the short term persistence of rainfall patterns across …

Automatic Synthesis Of Vlsi Layout For Analog Continuous-Time Filters, David Lyle Robinson

Dissertations and Theses

Automatic synthesis of digital VLSI layout has been available for many years. It has become a necessary part of the design industry as the window of time from conception to production shrinks with ever increasing competition. However, automatic synthesis of analog VLSI layout remains rare.

With digital circuits, there is often room for signal drift. In a digital circuit, a signal can drift within a range before hitting the threshold which triggers a change in logic state. The effect of parasitic capacitances for the most part, hinders the timing margins of the signal, but not its functionality. The logic functionality …

Erp Analysis Using Matched Filtering And Wavelet Transform, Xueming Lin

Dissertations and Theses

Event related potentials (ERP's) carry very important information that relates to the performance of the brain functions of the human being. Further studies have identified that one component, in particular, P₃₀₀, is affected by the memory process. Matched filter is used to improved the SNR of signal ERP's. We use the output of the matched filter to distinguish the difference of the waveforms between normal subjects and memory-impaired subjects. In our study, we found that the peak values of the matched filtering output were different between normal subjects and memoryimpaired subjects. Also, as an application, wavelet transform is …

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 …

Modeling And Simulation Of Bipolar Transistor At Low Temperature, Swarupa Madhav Nerurkar

Dissertations and Theses

The BICMOS technology which integrates the CMOS technology with bipolar technology has drawn considerable attention as an attractive VLSI technology because of the high speed performance and low power consumption of the BICMOS. However, continued down scaling of CMOS devices has caused increased concerns with problems such as latch up, hot carriers and short channel effect. Most of the above mentioned problems can be avoided by operating the CMOS at liquid-nitrogen temperature(LNT). At low-temperatures, the CMOS exhibits lower sub threshold leakage, higher carrier mobility (which yields improved speed performance), and a steeper logarithmic currentvoltage slope. On the other hand, the …

Pattern Recognition And Erp Waveform Analysis Using Wavelet Transform, Hong Qi

Dissertations and Theses

Wavelet transform provides an alternative to the classical Short-Time Fourier Transform (STFT). In contrast to the STFT, which uses a single analysis window, the Wavelet Transform uses shorter windows at higher frequencies and longer windows at lower frequencies. For some particular wavelet functions, the local maxima of the wavelet transform correspond to the sharp variation points of the signal. As an application, wavelet transform is introduced to the character recognition. Local maximum of wavelet transform is used as a local feature to describe character boundary. The wavelet method performs well in the presence of noise. The maximum of wavelet transform …

Unified Bias Analysis Of Subspace-Based Doa Estimation Algorithms, Yang Lu

Dissertations and Theses

This thesis presents the unified bias analysis of subspace-based DOA estimation algorithms in terms of physical parameters such as source separation, signal coherence, number of senors and snapshots. The analysis reveals the direct relationship between the performance of the DOA algorithms and signal measurement conditions. Insights into different algorithms are provided. Based upon previous first-order subspace perturbations, second-order subspace perturbations are developed which provide basis for bias analysis and unification. Simulations verifying the theoretical bias analysis are presented.