Engineering Commons^™

Fdtd And Fem/Mom Modeling Of Emi Resulting From A Trace Near A Pcb Edge, Daniel P. Berg, Motoshi Tanaka, Yun Ji, Xiaoning Ye, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

PCB traces routed near board edges and carrying high-speed signals are considered to contribute to EMI problems. Consequently, design maxims state that traces that might have intentional or unintentional high frequency components on them be kept away from board edges. This costs valuable surface area as boards become more densely designed. Further, design maxims concerning traces near board edges are not well quantified. The increase in EMI as a trace is routed increasingly closer to the PCB edge has been studied experimentally and with numerical modeling.

Experimental And Fdtd Study Of The Emi Performance Of An Open-Pin-Field Connector For Modules-On-Backplanes, Xiaoning Ye, Jim Nadolny, James L. Drewniak, Richard E. Dubroff, Thomas Van Doren, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

Experimental measurements and numerical modeling were used to study the EMI performance of a module-on-backplane connector for various configurations of signal-return pin-outs. A commercially available open-pin-field connector was used in these results to connect between the mother-board and the daughter-card. The experimental techniques, based on measuring |S₂₁|, included both common-mode current measurements and monopole near-field probe measurements. The FDTD method was used to provide numerical support of the near-field measurements and generally agreed with the measured results for frequencies up to 3 GHz. The FDTD method was also used to investigate the relationship between the radiated EMI at …

Distributed Arithmetic Implementation Of Multivariable Controllers For Smart Structural Systems, Lingfeng Yuan, Sridhar Sana, Hardy J. Pottinger, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Smart structural systems require the electronic control systems which are integrated into the structures to be small, lightweight and power-efficient. The field programmable gate array (FPGA) is a good platform to implement such controllers. In our previous work, FPGA-based digital controllers were built and tested on a simple structural system. In order to implement multivariable controllers, the hardware resources for FPGA-based architecture need to be further reduced. Distributed arithmetic (DA) has long been proven to be a very efficient means to mechanize computations that are dominated by inner products involving constant multiplicand. The computational requirements of the smart structural controllers …

Emc Analysis Of An 18" Lcd Monitor, Theodore M. Zeeff, Todd H. Hubing, James L. Drewniak, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes a case study covering the evaluation and reduction of the radiated EMI from an 18 inches Liquid Crystal Display (LCD) monitor. The evaluation was completed in two parts: first potential EMI sources at the Printed Circuit Board (PCB) level were identified, then the EMI antennas driven by these sources were analyzed. Methods for reducing the EMI were described in detail, and where applicable, those modifications were applied. Radiated measurements demonstrate the effectiveness of these recommendations.

Experimental Evaluation Of Power Bus Decoupling On A 4-Layer Printed Circuit Board, Juan Chen, Minjia Xu, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The switching of active devices on printed circuit boards (PCBs) can cause a momentary surge or drop in the power bus voltage. Decoupling capacitors are often utilized to alleviate this problem. They help to stabilize the power bus voltage by supplying transient current to active devices. The decoupling strategy, including where to place the high-frequency decoupling capacitors, is often a topic of debate. This paper examines the effect of decoupling capacitor placement on a 4-layer printed circuit board. Some design guidelines are provided.

Finite Element Modeling Of Patch Antenna And Cavity Sources, Yun Ji, Todd H. Hubing, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

This paper examines two different approaches that can be used to model patch antennas and cavities fed by a coaxial cable. The probe model represents the feed as a current filament along the center conductor of the coaxial cable. The coaxial-cable model enforces the analytical field distribution at the cable opening. These two models have been implemented in a hybrid FEM/MoM code. A power bus structure and a cavity geometry with coaxial-cable feeds are investigated. Numerical results obtained for these two examples are compared with measurements. It is shown that the probe model should only be applied to electrically short …

Development Of A Closed-Form Expression For The Input Impedance Of Power-Ground Plane Structures, Minjia Xu, Yun Ji, Todd H. Hubing, Thomas Van Doren, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

This paper analyzes the fundamental behavior of PCB power bus structures using the modal expansion method. The results are validated by experiments and full-wave numerical modeling. It is shown that the power bus can be modeled as a series L_eC circuit below the first board resonance frequency. C is the interplane capacitance and L_e is an effective inductance contributed by all the cavity nodes. The effects of the layer thickness, port location, board size and the feeding wire radius on the value of L_e are discussed in this study. L_e can be estimated from the …

The Emi Benefits Of Ground Plane Stitching In Multi-Layer Power Bus Stacks, Xiaoning Ye, David M. Hockanson, Min Li, Wei Cui, S. Radu, James L. Drewniak, Thomas Van Doren, Todd H. Hubing, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The effect on EMI of stitching multiple ground planes together along the periphery of multi-layer PCB stacks is studied. Power bus noise induced EMI and radiation from the board edges is the major concern herein. The EMI at 3 meters for different via stitch spacing and layer thickness is modeled with FDTD modeling. It is shown that the ground plane stitching effectively reduces the radiated EMI that results from fringing fields at the power bus edges. Two families of curves are generated to demonstrate the variation of the radiated EMI as a function of layer thickness and stitch spacing. Further …

Quantifying Decoupling Capacitor Location, Jun Fan, James L. Knighten, Antonio Orlandi, Norman W. Smith, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Decoupling capacitor location in DC power bus design is a critical design choice for which proven guidelines are not well established. The mutual inductance between two closely spaced vias can have a great impact on the coupling between an IC and a decoupling capacitor. This coupling is a function of the spacing between the IC and capacitor, and spacing between power and ground layers. The impact of the mutual inductance on decoupling, i.e., local versus global decoupling, was studied, using a circuit extraction approach based on a mixed-potential integral equation. Modeling indicates that local decoupling has benefits over global decoupling …

Real-Time Performance Analysis Of Wireless Multimedia Networks Based On Partially Observed Multivariate Point Processes, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

Third-generation (3G) wireless networks will support integrated multimedia services based on a cellular extension of a packet-switched architecture using variants of the Internet protocol (IP). Services can be categorized as real-time and delaysensitive, or non-real-time and delay-insensitive. Each call, arriving to or active within the network, carries demand for one or more services in parallel; each service type with a guaranteed quality of service (QoS). Admission of new calls to the wireless IP network (WIN) from the gateway of a wired network or from a mobile subscriber (MS) is allowed by call admission control (CAC) procedures. Roaming of the MSs …

Pattern Classification Approach To Underwater Acoustic Communications Based On The Wigner-Ville Distribution, Frank M. Caimi, Gamal A. Hassan

Electrical Engineering and Computer Science Faculty Publications

This paper describes an approach and preliminary results associated with the use of pattern recognition techniques to identify transmitted information (symbols) in a temporally variant acoustic channel. The method allows the observation of the transmitted signal simultaneously in both time and frequency space and does not necessarily rely on the application of adaptive algorithms for reception. The observation of the symbol energy from the Wigner-Ville Distribution as two-dimensional pattern can allow the determination of channel characteristics over short symbol sequences and can provide a means for symbol detection. For the QPSK modulation used, wavelet filtering provides a basis for noise …

2deg Channel-Dependent Model For Hg1-Xcdxte Based Pseudomorphic Hemts, Hang-Ming Dai, Thomas J. Sanders

Electrical Engineering and Computer Science Faculty Publications

HgCdTe has emerged as an important electronic material because of its IRFPA applications. Technologies for growing the material are advanced and current sources for the material are more readily available than in the past. This brings an advantage to the manufacturing other types of HgCdTe devices. PHEMTs are attractive as applications of high-speed devices. In this paper, a model for PHEMT devices by using Hg1 Cd1Te as device materials is presented. High digital performance of the device is expected because electron mobility ofthe material is very high at low temperatures.

Computation For Crosstalk Effects In P-On-N Hg1-Xcdxte Heterojunction Irfpa Radiated By Using Uniformly Parallel Light, Hang-Ming Dai, Thomas J. Sanders

Electrical Engineering and Computer Science Faculty Publications

in our work, a three-dimensional IRFPA model has been constructed to conduct device simulations for drift-diffusion based Hg1 CdTe devices. The model uses the finite element method and numerical errors are automatically eliminated during computation. Computational results can thus easily achieve accuracy. The computer model was constructed by using C++ language. We have successfully represented simulation results in three-dimensional graphics. In this paper, a model for analyzing infrared-illuminated p-on-n photodiodes is presented. The computational results were verified analytically and experimentally. Furthermore, an IRFPA device model was built for calculating crosstalk by using uniformly collimated infrared radiation. Devices used for the …

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the finite difference time domain (FDTD) and method of moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently used techniques, and can substantially improve the …

Electrical Properties Of Rapid Thermal Oxides On Si1−X−YGeXCY Films, L. K. Bera, W. K. Choi, W. Feng, Cary Y. Yang, J. Mi

Electrical and Computer Engineering

The electrical characteristics of rapid thermal oxides on Si_1−x−yGe_xC_y layers are reported. X-ray photoelectron spectroscopy results indicate segregation of Ge at the SiO₂/Si_1−x−yGe_xC_y interface, a thin GeO₂ layer at the oxide surface, and elemental Ge at the interface and in the oxide. The interface state density of the samples ranges from 3.0×10¹¹ to 3.6×10¹² eV⁻¹ cm⁻². All the samples show electron trapping behavior and the trap generation rate decreases with increasing C concentration. The charge-to-breakdown value and the oxide breakdown field are …

Thermal Lattice Boltzmann Simulation For Multispecies Fluid Equilibration, Linda L. Vahala, Darren Wah, George Vahala, Jonathan Carter, Pavol Pavlo

Electrical & Computer Engineering Faculty Publications

The equilibration rate for multispecies fluids is examined using thermal lattice Boltzmann simulations. Two-dimensional free-decay simulations are performed for effects of velocity shear layer turbulence on sharp temperature profiles. In particular, parameters are so chosen that the lighter species is turbulent while the heavier species is laminar-and so its vorticity layers would simply decay and diffuse in time. With species coupling, however, there is velocity equilibration followed by the final relaxation to one large co- and one large counter-rotating vortex. The temperature equilibration proceeds on a slower time scale and is in good agreement with the theoretical order of magnitude …

Optical Properties Of Bulk And Thin-Film Srtio3 On Si And Pt, Stefan Zollner, A. A. Demkov, R. Liu, P. L. Fejes, R.B. Gregory, Prasad Alluri, J. A. Curless, Z. Yu, J. Ramdani, R. Droopad, T. E. Tiwald, J. N. Hilfiker, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

We have studied the optical properties (complex dielectric function) of bulk SrTiO₃ and thin films on Si and Pt using spectroscopic ellipsometry over a very broad spectral range, starting at 0.03 eV [using Fourier transform infrared (FTIR) ellipsometry] to 8.7 eV. In the bulk crystals, we analyze the interband transitions in the spectra to determine the critical-point parameters. To interpret these transitions, we performed band structure calculations based on ab initio pseudopotentials within the local-density approximation. The dielectric function was also calculated within this framework and compared with our ellipsometry data. In the FTIR ellipsometry data, we notice a …

Numerical Simulation Of Acoustic Wave In A Convergent-Divergent Nozzle Using A Characeristic Based Algorithm, Haitham Maher Mahmoud

Archived Theses and Dissertations

No abstract provided.

Neural Networks Versus Nonparametric Neighbor-Based Classifiers For Semisupervised Classification Of Landsat Thematic Mapper Imagery, Perry J. Hardin

Faculty Publications

Semisupervised classification is one approach to converting multiband optical and infrared imagery into landcover maps. First, a sample of image pixels is extracted and clustered into several classes. The analyst next combines the clusters by hand to create a smaller set of groups that correspond to a useful landcover classification. The remaining image pixels are then assigned to one of the aggregated cluster groups by use of a per-pixel classifier. Since the cluster aggregation process frequently creates groups with multivariate shapes ill suited for parametric classifiers, there has been renewed interest in nonparametric methods for the task. This research reports …

Routing Optimization Through Computer-Aided Simulation, Madhusudhan Akundi

Electrical & Computer Engineering Theses & Dissertations

Routing has always been a challenging field, and the various techniques of mathematics and operations research have been developed. For commercial organizations, routing has begun to receive extensive attention because of the savings gained in terms of time, money, personnel, and the transportation fleet by developing optimized routing networks. Until recently, it was difficult to develop optimized networks due to the computational difficulties of the problem. However, with the advancement in computer technology and processing speeds, it has become possible to simulate a large number of routing scenarios and determine optimal solutions for a given set of constraints. Not only …

The Fundamental Use And Extension Of Mode Stirred Chambers, Stephen A. Scearce

Electrical & Computer Engineering Theses & Dissertations

Mode stirred chambers are used to perform radiated susceptibility tests on equipment that is expected to operate normally when exposed to electromagnetic (EM) fields. These tests are useful in identifying failure events in airborne equipment and other electronic equipment that are exposed to EM fields. This thesis is focused on further defining the operating environment of mode stirred chambers and relating the electromagnetic environment in the chamber to the electromagnetic environment of an actual aircraft. The majority of mode stirred chamber tests are implemented by using mechanical mode stirring. Mechanical mode stirring is the process of varying boundary conditions in …

Azimuth Variation In Microwave Scatterometer And Radiometer Data Over Antarctica, David G. Long, Mark R. Drinkwater

Faculty Publications

While designed for ocean observation, scatterometer and radiometer data have proven very useful in a variety of cryosphere studies. Over large regions of Antarctica, ice sheet and bedrock topography and the snow deposition, drift, and erosional environment combine to produce roughness on various scales. Roughness ranges from broad, basin-scale ice-sheet topography at 100 km wavelengths to large, spatially coherent dune fields at 10 km wavelength to erosional features on the meter scale known as sastrugi. These roughness scales influence the microwave backscattering and emission properties of the surface, combining to introduce azimuth-angle dependencies in the satellite observation data. In this …

Simulation Studies Of Cellular Electroporation Due To Ultra-Fast Electric Pulses, Gayathri R. Barthaki

Electrical & Computer Engineering Theses & Dissertations

Biological systems, from cells to ecosystems, are intrinsically complex information-processing networks. It often becomes difficult to predict their behavior during an experimental investigation, as their behavior is fundamentally chaotic, Hence, building models that mimic the dynamics of such systems and performing computer simulations would help in understanding, predicting, controlling and optimizing these systems. This thesis is aimed at the development of a mathematical model for the process of electroporation in biological cells when they are subjected to ultra-fast electric pulses and at conducting simulations to understand its dynamic behavior with special emphasis on the physics of ultra-short time scales.

With …

Signal Modeling With Non-Uniform Time Sampling Of Features For Automatic Speech Recognition, Montri Karnjanadecha

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents an investigation of non-uniform time sampling methods for spectral/temporal feature extraction in speech. Frame-based features were computed based on an encoding of the global spectral shape using a Discrete Cosine Transform. In most current “standard” methods, trajectory (dynamic) features are determined from frame-based parameters using a fixed time sampling, i.e., fixed block length and fixed block spacing. In this research, new methods are proposed and investigated in which block length and/or block spacing are variable. The idea was initially tested with HMM-based isolated word recognition, and a significant performance improvement resulted when a variable block length and …

Resolution Of Overlapping Spectra By Wavelength Modulation Spectroscopy, Audra Michiele Bullock

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation absorption spectroscopy is a highly sensitive, non-intrusive technique for probing gaseous species, which employs the well-known principles of modulation spectroscopy in a novel way. With this technique, parameters such as velocity, density, and temperature can be measured with a high degree of precision. The research presented here shows that wavelength modulation is a convenient means of increasing the sensitivity of an absorption spectroscopy measurement because it allows for harmonic detection. The focus of the dissertation is resolution of overlapping spectra by harmonic detection and the advantages gained by performing detection at the higher harmonics, e.g., sixth and eighth. …

Advanced Atmospheric Water Vapor Dial Detection System, Tamer Refaat

Electrical & Computer Engineering Theses & Dissertations

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface.

This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto …

An Improved Statcom Model For Power Flow Analysis, Zhiping Yang, Chen Shen, Lingli Zhang, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The StatCom is traditionally modeled for power flow analysis as a PV or PQ bus depending on its primary application. The active power is either set to zero (neglecting the StatCom losses) or calculated iteratively. The StatCom voltage and reactive power compensation are usually related through the magnetics of the StatCom. This traditional power flow model of the StatCom neglects the impact of the high-frequency effects and the switching characteristics of the power electronics on the active power losses and the reactive power injection (absorption). In this paper, the authors propose a new StatCom model appropriate for power flow analysis …

Role Of Laboratory Education In Power Engineering: Is The Virtual Laboratory Feasible? Part I, S. Iwamoto, G. G. Karady, Kraig J. Olejniczak, H. A. Mantooth, Mariesa Crow, Gerald T. Heydt

Electrical and Computer Engineering Faculty Research & Creative Works

IEEE PES sponsors a panel session in the summer power meeting in Seattle on laboratory education in power engineering. Six short papers and one full paper summarize the opinions of the panelist. This paper contains the summary of four of the presentations. The objective of the panel is to discuss the role of laboratory education in power engineering at both the graduate and undergraduate level. The question is what type of laboratory course is needed? Power electronics, electric machines, system simulation, etc? the second objective is to assess the status and value of computer based virtual laboratories. This includes the …

An Iterative Approach To Multisensor Sea Ice Classification, David G. Long, Mark R. Drinkwater, Quinn P. Remund

Faculty Publications

Characterizing the variability in sea ice in the polar regions is fundamental to an understanding of global climate and the geophysical processes governing climate changes. Sea ice can be grouped into a number of general classes with different characteristics. Multisensor data from NSCAT, ERS-2, and SSM/I are reconstructed into enhanced resolution imagery for use in ice-type classification. The resulting twelve-dimensional data set is linearly transformed through principal component analysis to reduce data dimensionality and noise levels. An iterative statistical data segmentation algorithm is developed using maximum likelihood (ML) and maximum a posteriori (MAP) techniques. For a given ice type, the …

Diversity Performance Of Dual-Antenna Handsets Near Operator Tissue, Michael A. Jensen, Bruce M. Green

Faculty Publications

This paper presents a computational and experimental study of the diversity performance of two dual-antenna handsets operating indoors in the 902-928 MHz industrial, scientific, and medical (ISM) band. Of particular interest is the effect of the operator tissue on the diversity operation. Key indicators of diversity gain such as branch mean effective gain (MEG) and envelope correlation coefficient are obtained from finite-difference time-domain (FDTD) method simulations as well as from experimental measurements in three different indoor environments. Diversity gain for the handsets is also measured directly. Reasonable agreement is observed between the experimental and simulated results, with both approaches indicating …