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Electrical and Computer Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

The Equivalent Circuit Model For Electrostatic And Magnetostatic Biased Tunable Graphene As The Absorption Material, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli Jul 2016

The Equivalent Circuit Model For Electrostatic And Magnetostatic Biased Tunable Graphene As The Absorption Material, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

Graphene is being proposed as a new nano material for EMC shielding and absorption due to its tunable resistive characteristics. The surface conductivity of graphene can be flexibly tuned by the electrostatic and magnetostatic bias applied on the graphene surface. Hence, its absorption and radiation characteristics of graphene are changed accordingly. The static electric bias applied on the graphene patch can change the chemical potential and the surface conductivity of graphene. The static magnetic field can make the conductivity a dispersive and anisotropic tensor, which complicates most modeling methodologies. In this paper, a novel equivalent circuit model is proposed for …

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A Novel Data Pattern Dependent Electromagnetic Emission Modeling For High Speed Multi-Channel Interconnects, Nick K.H. Huang, Li (Lijun) Jun Jiang, Xingyun Luo, Huichun Yu, Huasheng Ren Jul 2016

A Novel Data Pattern Dependent Electromagnetic Emission Modeling For High Speed Multi-Channel Interconnects, Nick K.H. Huang, Li (Lijun) Jun Jiang, Xingyun Luo, Huichun Yu, Huasheng Ren

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) is becoming more serious when the data rate of the digital system continues increasing. However, its modeling and analysis are very challenging. In this paper, a novel electromagnetic superposition method is developed to model the electromagnetic emission for the high speed multi-channels on IC packagings. It employs the equivalence principle to obtain the electromagnetic field response over a broad spectrum. Then it uses the linear property of the passive parasitic system to superpose the contribution of different signal patterns. As a result, with limited pre-calculations, it is very convenient to compute the electromagnetic emission efficiently from different …

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Linear Precoding For Cognitive Multiple Access Wiretap Channel With Finite-Alphabet Inputs, Juening Jin, Chengshan Xiao, Meixia Tao, Wen Chen Jul 2016

Linear Precoding For Cognitive Multiple Access Wiretap Channel With Finite-Alphabet Inputs, Juening Jin, Chengshan Xiao, Meixia Tao, Wen Chen

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the linear precoder design for cognitive multiple-access wiretap channel (CMAC-WT), where two secondary-user transmitters (STs) communicate with one secondary-user receiver (SR) in the presence of an eavesdropper and subject to interference threshold constraints at primary-user receivers (PRs). It designs linear precoders to maximize the ergodic secrecy sum rate for multiple-input multiple-output (MIMO) CMAC-WT under finite-alphabet inputs and statistical channel state information (CSI). For this non-convex problem, a two-layer algorithm is proposed by embedding the convex-concave procedure into an outer approximation framework. The key idea of this algorithm is to reformulate the approximated ergodic secrecy sum rate as …

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Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao Jul 2016

Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao

Electrical and Computer Engineering Faculty Research & Creative Works

A novel transient field-circuit simulation method based on the time-domain integral equation (TDIE) and circuit macromodels is proposed. The traditional field-circuit simulation process constructs Kirchoff's equations for linear or nonlinear lumped circuits, which cannot handle problems with unknown circuit structure. The proposed method creates parametric behavior macromodels to represent the port constitutive relations of the circuits. Artificial neural network technique is adopted to estimate the model parameters based on the known port voltages and currents. Then, the obtained macromodel is coupled with TDIE that describes the behavior of electromagnetic subsystem to form the equations of a whole system, which can …

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Effect Of Exposure Conditions On The Long-Term Dielectric Properties Of Mortar Samples Containing Asr Gel, Ashkan Hashemi, Kristen M. Donnell, R. Zoughi, Mehdi Rashidi, K. E. Kurtis Jul 2016

Effect Of Exposure Conditions On The Long-Term Dielectric Properties Of Mortar Samples Containing Asr Gel, Ashkan Hashemi, Kristen M. Donnell, R. Zoughi, Mehdi Rashidi, K. E. Kurtis

Electrical and Computer Engineering Faculty Research & Creative Works

Alkali-silica reaction (ASR) is a chemical reaction between alkalis present in portland cement and amorphous or otherwise disordered siliceous minerals in particular aggregates. Through this reaction, reactive silica binds with hydroxyl and alkali ions and forms a gel, known as ASR gel. Recently, microwave materials characterization techniques have shown great potential for detecting ASR in mortar. However, the comprehensive understanding of variables that affect the extent of ASR in mortar and their interaction with microwave signals, in particular the effect of environmental exposure conditions requires more investigations. Therefore, parameters related to these conditions must be considered when using microwave techniques …

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Multi-Sensor Integration To Map Odor Distribution For The Detection Of Chemical Sources, Xiang Gao, Levent Acar Jul 2016

Multi-Sensor Integration To Map Odor Distribution For The Detection Of Chemical Sources, Xiang Gao, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors' data at different positions. Initially, a multi-sensor integration method, together …

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Managing Contingencies In Smart Grids Via The Internet Of Things, Stefano Ciavarella, Jhi Young Joo, Simone Silvestri Jul 2016

Managing Contingencies In Smart Grids Via The Internet Of Things, Stefano Ciavarella, Jhi Young Joo, Simone Silvestri

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a framework for contingency management using smart loads, which are realized through the emerging paradigm of the Internet of things. The framework involves the system operator, the load serving entities (LSEs), and the end-users with smart home management systems that automatically control adjustable loads. The system operator uses an efficient linear equation solver to quickly calculate the load curtailment needed at each bus to relieve congested lines after a contingency. Given this curtailment request, an LSE calculates a power allowance for each of its end-use customers to maximize the aggregate user utility. This large-scale NP-hard problem is …

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Secure Massive Mimo Transmission With An Active Eavesdropper, Yongpeng Wu, Robert Schober, Derrick Wing Kwan Ng, Chengshan Xiao, Giuseppe Caire Jul 2016

Secure Massive Mimo Transmission With An Active Eavesdropper, Yongpeng Wu, Robert Schober, Derrick Wing Kwan Ng, Chengshan Xiao, Giuseppe Caire

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure and reliable transmission strategies for multi-cell multi-user massive multiple-input multiple-output systems with a multi-Antenna active eavesdropper. We consider a time-division duplex system where uplink training is required, and an active eavesdropper can attack the training phase to cause pilot contamination at the transmitter. This forces the precoder used in the subsequent downlink transmission phase to implicitly beamform toward the eavesdropper, thus increasing its received signal power. Assuming matched filter precoding and artificial noise (AN) generation at the transmitter, we derive an asymptotic achievable secrecy rate when the number of transmit antennas approaches infinity. For …

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Simultaneous Specimen Current And Time-Dependent Cathodoluminescence Measurements On Gallium Nitride, E. M. Campo, L. Hopkins, M. Pophristic, I. T. Ferguson Jun 2016

Simultaneous Specimen Current And Time-Dependent Cathodoluminescence Measurements On Gallium Nitride, E. M. Campo, L. Hopkins, M. Pophristic, I. T. Ferguson

Electrical and Computer Engineering Faculty Research & Creative Works

Time-dependent cathodoluminescence (CL) and specimen current (SC) are monitored to evaluate trapping behavior and evolution of charge storage. Examination of CL and SC suggests that the near band edge emission in GaN is reduced primarily by the activation of traps upon irradiation, and Gallium vacancies are prime candidates. At the steady state, measurement of the stored charge by empiric-analytical methods suggests that all available traps within the interaction volume have been filled, and that additional charge is being stored interstitially, necessarily beyond the interaction volume. Once established, the space charge region is responsible for the steady state CL emission and, …

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Waveguide Probe For Nondestructive Material Characterization, Mohammad Tayeb Ahmad Ghasr, Matthew Kempin, R. Zoughi Jun 2016

Waveguide Probe For Nondestructive Material Characterization, Mohammad Tayeb Ahmad Ghasr, Matthew Kempin, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

An open-ended waveguide probe including a finite flange extending outwardly and functioning as an infinite flange. A signal source provides a microwave signal to the waveguide, which in turn transmits microwave electromagnetic energy incident upon an object to be tested. The finite flange at the waveguide's aperture is shaped to reduce scattering of the electromagnetic field reflected from the object and received by the aperture. The probe is adapted for coupling to a receiver for sampling the reflected electromagnetic field received by the aperture and the receiver is adapted for coupling to a processor for determining at least one material …

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A Comprehensive Analytical Study Of Dielectric Modulated Drift Regions-Part I: Static Characteristics, Jiuyang Zhou, Chih Fang Huang, Chia Hui Cheng, Feng Zhao Jun 2016

A Comprehensive Analytical Study Of Dielectric Modulated Drift Regions-Part I: Static Characteristics, Jiuyang Zhou, Chih Fang Huang, Chia Hui Cheng, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

A comprehensive study of dielectric modulated (DM) drift regions for power devices is presented in this paper. The performance of this structure is theoretically analyzed and compared with both conventional and super junction (SJ) structures. In this paper, an analytical model for DM drift regions with cylindrical cells is proposed and compared with linear cells. An optimal tradeoff between breakdown voltage (BV) and specific ON-resistance (R ON,sp) is obtained by a methodology developed in this paper. 3-D simulations of DM structures with hexagonal cells approximated by cylindrical cells are conducted to verify the analytical model. Optimal BV-R ON,sp tradeoffs for …

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A Comprehensive Analytical Study On Dielectric Modulated Drift Regions-Part Ii: Switching Performances, Chih Fang Huang, Jiuyang Zhou, Chia Hui Cheng, Feng Zhao Jun 2016

A Comprehensive Analytical Study On Dielectric Modulated Drift Regions-Part Ii: Switching Performances, Chih Fang Huang, Jiuyang Zhou, Chia Hui Cheng, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

A comprehensive study on the dielectric modulated (DM) drift region for power devices is presented in this paper. The performance of this drift region structure is theoretically analyzed and compared with other two structures: conventional and super junction. In this paper, a study is focused on switching performance. The C-V relationships during switching are analytically derived, and the depletion widths predicted by the proposed analytical model agree well with simulation in a wide reverse bias region. The switching energy loss is evaluated based on the analytical model and its accuracy is verified by 2-D simulations. An effective depletion charge Q …

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Proportionate Affine Projection Algorithms For Block-Sparse System Identification, Jianming Liu, Steven L. Grant May 2016

Proportionate Affine Projection Algorithms For Block-Sparse System Identification, Jianming Liu, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A new family of block-sparse proportionate affine projection algorithms (BS-PAPA) is proposed to improve the performance for block-sparse systems. This is motivated by the recent block-sparse proportionate normalized least mean square (BS-PNLMS) algorithm. It is demonstrated that the affine projection algorithm (APA), proportionate APA, (PAPA), BS-PNLMS and PNLMS are all special cases of the proposed BS-PAPA algorithm. Meanwhile, an efficient implementation of the proposed BS-PAPA and block-sparse memory PAPA (BS-MPAPA) are also presented to reduce computational complexity. Simulation results demonstrate that the proposed BS-PAPA and BS-MPAPA algorithms outperform the APA, PAPA and MPAPA algorithms for block-sparse system identification in terms …

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An Accurate Method Of Energy Use Prediction For Systems With Known Consumption, Jacob A. Mueller, Jonathan W. Kimball May 2016

An Accurate Method Of Energy Use Prediction For Systems With Known Consumption, Jacob A. Mueller, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

An improved method of nonintrusive load monitoring (NILM) using hidden Markov models is proposed. The proposed method is intended for electrical systems with a closed and known set of devices. Systems that meet this constraint are more commonly found in industrial or commercial contexts than the residential settings in which NILM is traditionally studied. The proposed method is designed to support applications relevant to these contexts, such as fault monitoring and system health assessments. To this end, the energy predictions of the disaggregation algorithm offer accurate descriptions of device behavior in time. The accuracy of the proposed method is validated …

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Nonlinear I/O Characterization With The Time Domain Electromagnetic Simulations, Li (Lijun) Jun Jiang, Huan Huan Zhang, Ying S. Cao, Ping Li May 2016

Nonlinear I/O Characterization With The Time Domain Electromagnetic Simulations, Li (Lijun) Jun Jiang, Huan Huan Zhang, Ying S. Cao, Ping Li

Electrical and Computer Engineering Faculty Research & Creative Works

Computational electromagnetic algorithms are indispensible to today's electromagnetic compatibility. However the nonlinear I/O modeling and its hybridized simulation with electromagnetic solvers were less addressed. In this paper, we discuss two major solutions we proposed for nonlinear I/O modeling. When the details of the circuit are given known, the SPICE circuit model can be employed in the simulation. However when the detail of the nonlinear I/O is not known, which happens often, a parametric macro model is first developed to replace the I/O before the hybridized characterization. The proposed techniques are mostly suitable for time domain based computational electromagnetics systems.

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The Derived Equivalent Circuit Model For Non-Magnetized And Magnetized Graphene, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli May 2016

The Derived Equivalent Circuit Model For Non-Magnetized And Magnetized Graphene, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, for the first time the electromagnetic features of graphene are characterized by a circuit model derived instead of fitted from the electric field integral equation (EFIE). The atomically thick graphene is equivalently replaced by an impedance surface. When it is magnetized, the impedance surface is anisotropic with a tensor conductivity. Based on EFIE, the graphene's circuit model can be derived by the partial element equivalency circuit (PEEC) concept. The anisotropic resistivity is modeled using a serial resistor with current control voltage sources (CCVSs). From the derived circuit model, electromagnetic properties of graphene can be conveniently analyzed. This …

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Pwm-Controlled Dc-Dc Converter Designs In 3d Ics Using Through-Silicon-Via Inductors, Prateek N. Kankonkar, Umamaheswara Rao Tida, Cheng Zhou, Yiyu Shi May 2016

Pwm-Controlled Dc-Dc Converter Designs In 3d Ics Using Through-Silicon-Via Inductors, Prateek N. Kankonkar, Umamaheswara Rao Tida, Cheng Zhou, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

There has been a tremendous research effort in recent years to move DC-DC converters on chip for enhanced performance. To reduce the large area overhead induced by conventional spiral inductors, existing literature has used through-silicon-vias (TSVs) inductors in basic DC-DC converters without feedback control. In this paper, we further study the possible application of TSV inductors in DC-DC converters with Pulse Width Modulation (PWM)-controlled feedback. The DC-DC converter with TSV inductor is at par in terms of performance with other conventional designs in the literature. Experimental results show that by replacing conventional spiral inductors with TSV inductors, up to 4.3x …

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A Brief Review Of Security In Emerging Programmable Computer Networking Technologies, Egemen K. Çetinkaya May 2016

A Brief Review Of Security In Emerging Programmable Computer Networking Technologies, Egemen K. Çetinkaya

Electrical and Computer Engineering Faculty Research & Creative Works

Recent programmable networking paradigms, such as cloud computing, fog computing, software- defined networks, and network function virtualization gain significant traction in industry and academia. While these newly developed networking technologies open a pathway to new architectures and enable a faster innovation cycle, there exist many problems in this area. In this article, we provide a review of these programmable networking architectures for comparison. Second, we provide a survey of security attacks and defense mechanisms in these emerging programmable networking technologies.

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Improving Kinematic Accuracy Of Soft Wearable Data Gloves By Optimizing Sensor Locations, Donghyun Kim, Sang Wook Lee, Hyung-Soon Park May 2016

Improving Kinematic Accuracy Of Soft Wearable Data Gloves By Optimizing Sensor Locations, Donghyun Kim, Sang Wook Lee, Hyung-Soon Park

Electrical and Computer Engineering Faculty Research & Creative Works

Bending sensors enable compact, wearable designs when used for measuring hand configurations in data gloves. While existing data gloves can accurately measure angular displacement of the finger and distal thumb joints, accurate measurement of thumb carpometacarpal (CMC) joint movements remains challenging due to crosstalk between the multi-sensor outputs required to measure the degrees of freedom (DOF). To properly measure CMC-joint configurations, sensor locations that minimize sensor crosstalk must be identified. This paper presents a novel approach to identifying optimal sensor locations. Three-dimensional hand surface data from ten subjects was collected in multiple thumb postures with varied CMC-joint flexion and abduction …

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A Study Of Single Scattering Of Scatterer At Various Orientation Angles With Equivalence Principle Algorithm, Chan Fai Lum, Hong Tat Ewe, Fu-Xin, Li (Lijun) Jun Jiang Apr 2016

A Study Of Single Scattering Of Scatterer At Various Orientation Angles With Equivalence Principle Algorithm, Chan Fai Lum, Hong Tat Ewe, Fu-Xin, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

It is common that spherical scatterers are used to represent air bubbles or brine inclusions embedded in the snow or sea ice layer. This physical configuration is then solved using radiative transfer theory to obtain backscattering coefficient from the snow or sea ice layer. With the advent of new techniques in computational electromagnetics, the typical theoretical model of single layer of snow or sea ice can be easily extended to consider types of scatterers which are of other shapes or irregular shapes. A computational electromagnetic method based on equivalence principle algorithm can be incorporated into existing theoretical model to calculate …

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Free-Hand Scanning And Imaging, Joseph T. Case, Mohammad Tayeb Ahmad Ghasr, R. Zoughi Apr 2016

Free-Hand Scanning And Imaging, Joseph T. Case, Mohammad Tayeb Ahmad Ghasr, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Wideband synthetic aperture radar (SAR) imaging. A probe transmits a signal through its aperture incident to an object located in a medium of interest remotely from the probe. The probe receives through the aperture a plurality of nonuniformly sampled reflected signals from the object as the probe moves in a measurement plane located a predetermined distance from the object. A processor executes a SAR-based reconstruction algorithm to generate an image.

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A Dgtd Scheme For Modeling The Radiated Emission From Duts In Shielding Enclosures Using Near Electric Field Only, Ping Li, Yifei Shi, Li (Lijun) Jun Jiang, Hakan Baǧci Apr 2016

A Dgtd Scheme For Modeling The Radiated Emission From Duts In Shielding Enclosures Using Near Electric Field Only, Ping Li, Yifei Shi, Li (Lijun) Jun Jiang, Hakan Baǧci

Electrical and Computer Engineering Faculty Research & Creative Works

To meet the electromagnetic interference regulation, the radiated emission from device under test such as electronic devices must be carefully manipulated and accurately characterized. Instead of resorting to the direct far-field measurement, in this paper, a novel approach is proposed to model the radiated emission from electronic devices placed in shielding enclosures by using the near electric field only. Based on the Schelkkunoff's equivalence principle and Raleigh-Carson reciprocity theorem, only the tangential components of the electric field over the ventilation slots and apertures of the shielding enclosure are sufficient to obtain the radiated emissions outside the shielding box if the …

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A Frequency-Independent Method For Computing The Physical Optics-Based Electromagnetic Fields Scattered From A Hyperbolic Surface, Yu Mao Wu, Weng Cho Chew, Ya Qiu Jin, Li (Lijun) Jun Jiang, Hongxia Ye, Wei E.I. Sha Apr 2016

A Frequency-Independent Method For Computing The Physical Optics-Based Electromagnetic Fields Scattered From A Hyperbolic Surface, Yu Mao Wu, Weng Cho Chew, Ya Qiu Jin, Li (Lijun) Jun Jiang, Hongxia Ye, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

In this communication, we propose a frequency-independent approach, the numerical steepest descent path (NSDP) method, for computing the physical optics scattered electromagnetic field on the quadratic hyperbolic surface. Due to the highly oscillatory nature of the physical optics integral, the proposed method relies on deforming the integration path of the integral into the NSDP on the complex plane. Numerical results for the PO-based EM fields from the hyperbolic surface illustrate that the proposed NSDP method is frequency independent in computational cost and error controllable in accuracy.

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Proportionate Adaptive Filtering For Block-Sparse System Identification, Jianming Liu, Steven L. Grant Apr 2016

Proportionate Adaptive Filtering For Block-Sparse System Identification, Jianming Liu, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new family of proportionate normalized least mean square (PNLMS) adaptive algorithms that improve the performance of identifying block-sparse systems is proposed. The main proposed algorithm, called block-sparse PNLMS (BS-PNLMS), is based on the optimization of a mixed norm of the adaptive filter's coefficients. It is demonstrated that both the NLMS and the traditional PNLMS are special cases of BS-PNLMS. Meanwhile, a block-sparse improved PNLMS (BS-IPNLMS) is also derived for both sparse and dispersive impulse responses. Simulation results demonstrate that the proposed BS-PNLMS and BS-IPNLMS algorithms outperformed the NLMS, PNLMS and IPNLMS algorithms with only a modest …

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An Information Exchange Framework Utilizing Smart Buildings For Efficient Microgrid Operation, Jhi Young Joo, Marija D. Ilić Apr 2016

An Information Exchange Framework Utilizing Smart Buildings For Efficient Microgrid Operation, Jhi Young Joo, Marija D. Ilić

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we propose an information exchange framework to incorporate smart building demands into a microgrid operation. We especially focus on scheduling smart building demand along with other possibly highly uncertain microgrid generation resources a day ahead or shorter ahead of operation. Since every building demand has different energy consumption profiles and dynamics, it is inefficient for the grid operator to directly control a potentially large number of buildings. On the other hand, if the grid operator does not have sufficient information on the buildings and their resource potentials, smart buildings cannot be deployed to the full extent. Our …

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Comparison Of Binary And Multi-Level Logic Electronics For Embedded Systems, Shirly M. Damti, Steve Eugene Watkins, R. Joe Stanley Apr 2016

Comparison Of Binary And Multi-Level Logic Electronics For Embedded Systems, Shirly M. Damti, Steve Eugene Watkins, R. Joe Stanley

Electrical and Computer Engineering Faculty Research & Creative Works

Embedded systems are dependent on low-power, miniaturized instrumentation. Comparator circuits are common elements in applications for digital threshold detection. A multi-level, memory-based logic approach is in development that offers potential benefits in power usage and size with respect to traditional binary logic systems. Basic 4-bit operations with CMOS gates and comparators are chosen to compare circuit implementations of binary structures and quaternary equivalents. Circuit layouts and functional operation are presented. In particular, power characteristics and transistor count are examined. The potential for improved embedded systems based on the multilevel, memory-based logic is discussed.

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A Fast Time-Domain Em-Tcad Coupled Simulation Framework Via Matrix Exponential With Stiffness Reduction, Quan Chen, Wim Schoenmaker, Shih Hung Weng, Chung Kuan Cheng, Guan Hua Chen, Li (Lijun) Jun Jiang, Ngai Wong Apr 2016

A Fast Time-Domain Em-Tcad Coupled Simulation Framework Via Matrix Exponential With Stiffness Reduction, Quan Chen, Wim Schoenmaker, Shih Hung Weng, Chung Kuan Cheng, Guan Hua Chen, Li (Lijun) Jun Jiang, Ngai Wong

Electrical and Computer Engineering Faculty Research & Creative Works

We present a fast time-domain multiphysics simulation framework that combines full-wave electromagnetism (EM) and carrier transport in semiconductor devices (technology computer-aided design (TCAD)) for radio frequency (RF) and mixed-signal modules. The proposed framework features a division of linear and nonlinear components in the EM-TCAD coupled system. The linear portion is extracted and handled independently with high efficiency by a matrix exponential approach assisted with Krylov subspace method. The nonlinear component is treated by ordinary Newton's method yet with a much sparser Jacobian matrix that leads to substantial speedup in solving the linear system of equations. More convenient error management and …

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An Equivalent Circuit Model For Graphene-Based Terahertz Antenna Using The Peec Method, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli Apr 2016

An Equivalent Circuit Model For Graphene-Based Terahertz Antenna Using The Peec Method, Ying S. Cao, Li (Lijun) Jun Jiang, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

The electromagnetic (EM) characterization of graphene under general EM environments is becoming of interest in the engineering and scientific research fields. However, its numerical modeling process is extremely cost prohibitive due to the huge contrast between its thickness and other dimensions. In this work, for the first time, the EM features of graphene are characterized by a circuit model through the partial element equivalent circuit (PEEC) method. The atomically thick graphene is equivalently replaced by an impedance boundary condition. After incorporating the PEEC method, a novel surface conductivity circuit model is derived for graphene. A physical resistor and inductor are …

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Synthesis Of Large-Scale 2-D Mos2 Atomic Layers By Hydrogen-Free And Promoter-Free Chemical Vapor Deposition, Hung Nguyen, Chih Fang Huang, Weijun Luo, Guangrui Xia, Zhiqiang Chen, Zhiqiang Li, Christopher Raymond, David Doyle, Feng Zhao Apr 2016

Synthesis Of Large-Scale 2-D Mos2 Atomic Layers By Hydrogen-Free And Promoter-Free Chemical Vapor Deposition, Hung Nguyen, Chih Fang Huang, Weijun Luo, Guangrui Xia, Zhiqiang Chen, Zhiqiang Li, Christopher Raymond, David Doyle, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

As one of the two-dimensional (2-D) transition metal dichalcogenides, atomically thin molybdenum disulfide (MoS2) has attracted significant attention and research interests for micro and nano electronic applications. Significant efforts have been made to develop different approaches in order to obtain atomic layer MoS2, such as exfoliation, chemical synthesis, and physical or chemical vapor deposition (CVD) processes. In this paper, we report a hydrogen-free and promoter-free CVD growth to synthesize large-area MoS2 atomic layers. A variety of techniques including optical microscopy (OM), atomic force microscopy (AFM), photoluminescence (PL) mapping, Raman and x-ray photoelectron spectroscopy (XPS), high resolution electron microscopy (HREM) and …

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Throughput Optimisation For Energy Harvesting Transmitter With Partial Instantaneous Channel State Information And Finite-Alphabet Inputs, Xiaodong Zhu, Weiliang Zeng, Chengshan Xiao Mar 2016

Throughput Optimisation For Energy Harvesting Transmitter With Partial Instantaneous Channel State Information And Finite-Alphabet Inputs, Xiaodong Zhu, Weiliang Zeng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless communication systems with energy harvester are attracting much attention due to their ability to improve the system operation time. Extensive research has been carried out on how to maximize the sum of mutual information over multiple time slots (i.e. the throughput). However, most research focuses on the energy harvesting transmitter with Gaussian inputs and single antenna. This study considers the throughput maximization problem for an energy harvesting transmitter with causal energy constraint over multiple-input multiple-output (MIMO) channels. Different from existing works, the authors consider the MIMO system with finite-alphabet inputs and partial instantaneous channel state information (CSI). Specifically, the …

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