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Electrical and Computer Engineering Faculty Research & Creative Works

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Empirical Modeling Of Contact Intermodulation Effect On Coaxial Connectors, Xiong Chen, Yongning He, Ming Yu, David J. Pommerenke, Jun Fan Jul 2020

Empirical Modeling Of Contact Intermodulation Effect On Coaxial Connectors, Xiong Chen, Yongning He, Ming Yu, David J. Pommerenke, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

An empirical modeling of contact nonlinearity-induced intermodulation (IM) effect on the coaxial connector is presented in this article. The IM weights on inner and outer conductors are clarified using the measurement method. The contact degeneration-induced IM evolution is quantized by considering the contact coupling effect between the inner and outer conductors. This article demonstrated a set of test methods to quantify the oxide-induced nonlinearity with contact degeneration effects, and these methods can evaluate the contact IM products and further predict the low IM lifetime of passive devices.


Decoupling Capacitor Power Ground Via Layout Analysis For Multi-Layered Pcb Pdns, Biyao Zhao, Shuang Liang, Samuel Connor, Matteo Cocchini, Brice Achkir, Albert E. Ruehli, Bruce Archambeault, Jun Fan, James L. Drewniak Jul 2020

Decoupling Capacitor Power Ground Via Layout Analysis For Multi-Layered Pcb Pdns, Biyao Zhao, Shuang Liang, Samuel Connor, Matteo Cocchini, Brice Achkir, Albert E. Ruehli, Bruce Archambeault, Jun Fan, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A modeling methodology to calculate the decoupling capacitor interconnect inductance in a multi-layer PCB is proposed herein. The methodology is based on the resonant cavity model of parallel planes. The self-inductance and mutual inductance are extracted to understand the via configuration influence on the effectiveness of decoupling capacitors. A special layout of decoupling capacitor is proposed to increase the effectiveness of the decoupling capacitors by taking maximum advantage of the mutual inductance between interconnect vias with two decoupling capacitors placed in a pair, and two pairs of power and ground vias placed in alternating directions as close as possible. The …


Effect Of Rf Signals On Tvs Diode Trigger Voltage For Esd Protection, Giorgi Maghlakelidze, Shubhankar Marathe, Wei Huang, Joost Willemen, David Pommerenke Jul 2020

Effect Of Rf Signals On Tvs Diode Trigger Voltage For Esd Protection, Giorgi Maghlakelidze, Shubhankar Marathe, Wei Huang, Joost Willemen, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Discrete transient voltage suppressor devices are used in addition to the on-chip ESD protection to protect the ICs from ESD damage. In applications involving snapback TVS devices, the trigger voltage is selected to be higher than the desired signals on the net. The presence of RF on the net affects the TVS behavior, even if the RF levels are less than the snapback trigger voltage. Known effects are RF intermodulation and harmonic generation, which diminish SNR. This work describes the other effect on the TVS diodes - the observed reduction of the snapback trigger voltage, monotonically dependent on the amplitude …


The Effect Of The Parallel-Plate Mode On Striplines In Inhomogeneous Dielectric Media, Jiayi He, Shaohui Yong, Zurab Kiguradze, Arun Chada, Bhyrav Mutnury, James Drewniak Jul 2020

The Effect Of The Parallel-Plate Mode On Striplines In Inhomogeneous Dielectric Media, Jiayi He, Shaohui Yong, Zurab Kiguradze, Arun Chada, Bhyrav Mutnury, James Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Strip lines are widely used in high speed printed circuit boards (PCB). When the strip line is in inhomogeneous dielectric media, its principal operation mode is quasi-TEM. In this case, the parallel-plate mode between two ground planes can be excited as a parasitic mode. This paper investigates the effect of this parasitic mode on strip lines through simulations. The simulated S-parameters of strip lines when this parallel-plate mode is excited and suppressed are compared. The measured S-parameters of strip lines with and without the ground stitching vias are also compared. The impact of the parasitic mode on time domain crosstalk …


A Study Of Coverlay Coated Microstrip Lines For Crosstalk Reduction In Ddr5, Qiang Ming Cai, Yuyu Zhu, Runren Zhang, Yinglei Ren, Xiaoning Ye, Jun Fan Jul 2020

A Study Of Coverlay Coated Microstrip Lines For Crosstalk Reduction In Ddr5, Qiang Ming Cai, Yuyu Zhu, Runren Zhang, Yinglei Ren, Xiaoning Ye, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

Crosstalk becomes a serious problem in microstrip design of printed circuit boards (PCBs) in DDR5. In high-density and high-speed PCBs, widening space or putting shielding between traces to mitigate crosstalk noise may become less effective, because of the limited space. This paper presents a simple and efficient crosstalk reduction approach by using coverlay coated microstrip lines. This coverlay is available in a variety of film and adhesive thicknesses, which is commonly used materials for the resistance welding transform in PCB production. Based on the simulated S-parameters, the FEXT keeps under -40 dB from dc to 16.0 GHz, and more than …


Low Emf Design Of Cochlear Implant Wireless Power Transfer System Using A Shielding Coil, Seokwoo Hong, Seungtaek Jeong, Seongsoo Lee, Boogyo Sim, Hongseok Kim, Joungho Kim Jul 2020

Low Emf Design Of Cochlear Implant Wireless Power Transfer System Using A Shielding Coil, Seokwoo Hong, Seungtaek Jeong, Seongsoo Lee, Boogyo Sim, Hongseok Kim, Joungho Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless power transfer (WPT) technology is widely used for various applications because of convenience and safety. Especially, medical implant devices such as a cochlear implant are one of the typical applications of the WPT technology. However, WPT systems have problems with electromagnetic field (EMF) leakage, which can cause electro-magnetic interference (EMI) issues in the human body. In this paper, we propose an additional shielding coil for the effective suppression of EMF radiation of a WPT system. The proposed method reduces the EMF leakage in operating frequency range. We verified that the proposed shielding coil reduced the EMF leakage by 5.1 …


Sensitivity Analysis Of Local Soldermask And Coverlay In High Speed Transimission Lines For Ddr5 Applications To Reduce Fext, Zhu Lin, Xin Cao, Qiang Ming Cai, Yinglei Ren, Xiaoning Ye, Jun Fan Jul 2020

Sensitivity Analysis Of Local Soldermask And Coverlay In High Speed Transimission Lines For Ddr5 Applications To Reduce Fext, Zhu Lin, Xin Cao, Qiang Ming Cai, Yinglei Ren, Xiaoning Ye, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

This article investigated the effects of local solder-mask and overlay structure changes on crosstalk. This structure is based on a four-layer high-speed PCB on a computer DDR5 board. Our goal is to use the obtained simulation results to locate the optimal response that not only meets the performance requirements but is also robust to geometric changes caused by manufacturing tolerances. These two methods have a good correlation with the simulation results and show strong capabilities in the practical applications.


High-Speed Channel Equalization Applying Parallel Bayesian Machine Learning, Zurab Kiguradze, Nana Dikhaminjia, Mikheil Tsiklauri, Jiayi He, Bhyrav Mutnury, Arun Chada, James L. Drewniak Jul 2020

High-Speed Channel Equalization Applying Parallel Bayesian Machine Learning, Zurab Kiguradze, Nana Dikhaminjia, Mikheil Tsiklauri, Jiayi He, Bhyrav Mutnury, Arun Chada, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Recovering attenuated signals caused by different issues including connections between connectors and chips of the devices, channel loss, and crosstalk is a challenging problem. Equalization is the most popular way to restore distorted signals. Different optimization algorithms are used to find the best tap coefficients for each equalization that improves eye opening and decreases the bit error rate (BER). Nowadays algorithms of equalization mainly operate to reduce the difference between input and output signals. In turn, this will increase eye height indirectly, but direct maximization of the eye height will restore the signal even better. The paper proposes a new …


Rfi Estimation For Multiple Noise Sources Due To Modulation At A Digital Mic Using Diople Moment Based Reciprocity, Shengxuan Xia, Jingdong Sun, Qiaolei Huang, Yansheng Wang, Hanfeng Wang, Ken Wu, Songping Wu, Jun Fan Jul 2020

Rfi Estimation For Multiple Noise Sources Due To Modulation At A Digital Mic Using Diople Moment Based Reciprocity, Shengxuan Xia, Jingdong Sun, Qiaolei Huang, Yansheng Wang, Hanfeng Wang, Ken Wu, Songping Wu, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

Non-ideal ground structures in flexible printed circuit board, such as the meshed ground or discrete ground nets, can cause severe RFI to the nearby antennas. Those RF radiators can be modeled as a set of equivalent dipole moment(s) when they are electrically small. Then, the dipole moment-based reciprocity theorem can be applied to estimate the noise coupling level. In this article, a practical methodology using the dipole moment-based reciprocity is proposed to identify multiple radiation sources of a real cellphone product. Multiple equivalent dipole moments are constructed with one-to-one correspondence to the physical structures. The reciprocity calculations can eventually provide …


Asymptotic Analysis For Overlap In Waveform Relaxation Methods For Rc Type Circuits, Martin J. Gander, Pratik M. Kumbhar, Albert E. Ruehli Jul 2020

Asymptotic Analysis For Overlap In Waveform Relaxation Methods For Rc Type Circuits, Martin J. Gander, Pratik M. Kumbhar, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

Waveform relaxation (WR) methods are based on partitioning large circuits into sub-circuits which then are solved separately for multiple time steps in so called time windows, and an iteration is used to converge to the global circuit solution in each time window. Classical WR converges quite slowly, especially when long time windows are used. To overcome this issue, optimized WR (OWR) was introduced which is based on optimized transmission conditions that transfer information between the sub-circuits more efficiently than classical WR. We study here for the first time the influence of overlapping sub-circuits in both WR and OWR applied to …


One-Dimensional Sensor Learns To Sense Three-Dimensional Space, Chen Zhu, Rex E. Gerald, Yizheng Chen, Jie Huang Jun 2020

One-Dimensional Sensor Learns To Sense Three-Dimensional Space, Chen Zhu, Rex E. Gerald, Yizheng Chen, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

A sensor system with ultra-high sensitivity, high resolution, rapid response time, and a high signal-to-noise ratio can produce raw data that is exceedingly rich in information, including signals that have the appearances of "noise". The "noise"feature directly correlates to measurands in orthogonal dimensions, and are simply manifestations of the off-diagonal elements of 2nd-order tensors that describe the spatial anisotropy of matter in physical structures and spaces. The use of machine learning techniques to extract useful meanings from the rich information afforded by ultra-sensitive one-dimensional sensors may offer the potential for probing mundane events for novel embedded phenomena. Inspired by our …


Channel Estimators For Full-Duplex Communication Using Orthogonal Pilot Sequences, Arul Mathi Maran Chandran, Lei Wang, Maciej Jan Zawodniok Jun 2020

Channel Estimators For Full-Duplex Communication Using Orthogonal Pilot Sequences, Arul Mathi Maran Chandran, Lei Wang, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Full-duplex communication is desirable to maximize the spectral efficiency, despite the challenges it puts forth. The key challenge inhibiting the operation of radios in full-duplex mode is self-interference. In this paper, we propose a pilot-based channel estimation to estimate both self-interference and communication channels simultaneously at both ends of a full-duplex link using orthogonal sequences. The Cramer-Rao Lower Bound for estimators of both the channels was determined and compared with the half-duplex channel estimator. We performed simulations varying sequence length and channel taps and studied the performance of the estimators. We also studied the effect of synchronization between the sequences …


Jet Ejection Following Drop Impact On Micropillared Hydrophilic Substrates, Anayet Ullah Siddique, Marcus Trimble, Feng Zhao, Mark M. Weislogel, Hua Tan Jun 2020

Jet Ejection Following Drop Impact On Micropillared Hydrophilic Substrates, Anayet Ullah Siddique, Marcus Trimble, Feng Zhao, Mark M. Weislogel, Hua Tan

Electrical and Computer Engineering Faculty Research & Creative Works

Droplet-wall interactions are well known to generate a wide variety of outcomes such as spreading, splashing, receding, jetting, and rebounding. In this paper, we focus on the evolution of jets that form during the recoil of impinging drops on partially wetting hydrophilic substrates composed of cylindrical micropillars. The impact of the millimeter-sized drops of water-glycerol mixtures on the micro structured hydrophilic substrates is investigated by high-speed video photography. Impact velocity and fluid viscosity are varied to characterize the jets. Wetting angles are maintained in the range of 43.6° ≤θ≤51.4°. A regime map is constructed to convey the jet behavior at …


Software-Based Monitoring And Analysis Of A Usb Host Controller Subject To Electrostatic Discharge, Natasha Jarus, Antonio Sabatini, Pratik Maheshwari, Sahra Sedigh Sarvestani Jun 2020

Software-Based Monitoring And Analysis Of A Usb Host Controller Subject To Electrostatic Discharge, Natasha Jarus, Antonio Sabatini, Pratik Maheshwari, Sahra Sedigh Sarvestani

Electrical and Computer Engineering Faculty Research & Creative Works

Observing, understanding, and mitigating the effects of failure in embedded systems is essential for building dependable control systems. We develop a software-based monitoring methodology to further this goal. This methodology can be applied to any embedded system peripheral and allows the system to operate normally while the monitoring software is running. We use software to instrument the operating system kernel and record indicators of system behavior. By comparing those indicators against baseline indicators of normal system operation, faults can be detected, and appropriate action can be taken. We implement this methodology to detect faults caused by electrostatic discharge in a …


Statistical Eye Diagram Analysis Based On Double-Edge Responses For Coding Buses, Xiuqin Chu, Wenwu Wang, Jun Wang, Xiangyu Dai, Jun Fan, Yushan Li Jun 2020

Statistical Eye Diagram Analysis Based On Double-Edge Responses For Coding Buses, Xiuqin Chu, Wenwu Wang, Jun Wang, Xiangyu Dai, Jun Fan, Yushan Li

Electrical and Computer Engineering Faculty Research & Creative Works

For high-speed coding buses, it is a great challenge to evaluate the eye diagram accurately. Assuming that all data bits are independent and have uniform probabilities as previous estimation methods have done is not valid. In this paper, a new statistical method is proposed to estimate the worst-case eye diagrams and bit-error-rate (BER) eye diagrams for coding buses. The probability distribution of coded bus bit vectors is modeled based on the coding rule constraints. Then, actual worst pattern and eye diagram calculation is derived based on bus bit transition probabilities and double-edge responses. In order to validate the method, a …


Rugged Linear Array For Iot Applications, Lidong Chi, Zi Bin Weng, Shu Meng, Yihong Qi, Jun Fan, Weihua Zhuang, James L. Drewniak Jun 2020

Rugged Linear Array For Iot Applications, Lidong Chi, Zi Bin Weng, Shu Meng, Yihong Qi, Jun Fan, Weihua Zhuang, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

In this article, a rugged linear array is proposed for covering both the LTE and 5G bands with an intermediate gain. The antenna is composed of a driven element, a set of directors, and a set of reflectors, where the excited element is a wideband high-efficiency electromagnetic structure (WHEMS) and the parasitic elements consist of metal rods. To achieve a rugged design, similar to the classic Yagi antenna, all of the elements should be conductively connected, so that it can be welded. The weldable mechanism is started on the driven radiating element. In addition, a balun is introduced in the …


A General And Systematic Method To Design Neutralization Lines For Isolation Enhancement In Mimo Antenna Arrays, Min Li, Lijun Jiang, Kwan Lawrence Yeung Jun 2020

A General And Systematic Method To Design Neutralization Lines For Isolation Enhancement In Mimo Antenna Arrays, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

A general and systematic approach is the first time proposed in this paper to design the neutralization line (NL) for isolation enhancement in multiple-input multiple-output (MIMO) antenna arrays. Each NL consists of a metal strip and a reactive component attached at its middle position. It is connected with every two antenna radiators to generate an additional coupling path against the original antenna coupling for isolation enhancement. A general network model that leads to a systematic design procedure is developed to meet the required isolation criteria. Three practical examples are presented and used to verify the proposed NL-based decoupling technique (DT). …


Dc Ir-Drop Analysis Of Multilayered Power Distribution Network By Discontinuous Galerkin Method With Thermal Effects Incorporated, Ping Li, Min Tang, Zhi Xiang Huang, Li (Lijun) Jun Jiang, Hakan Bagci Jun 2020

Dc Ir-Drop Analysis Of Multilayered Power Distribution Network By Discontinuous Galerkin Method With Thermal Effects Incorporated, Ping Li, Min Tang, Zhi Xiang Huang, Li (Lijun) Jun Jiang, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

Due to the temperature-dependent resistivity of power distribution network (PDN) interconnects, a wiser and necessary strategy is to proceed the electrical-thermal cosimulation in order to include the thermal effects caused by Joule heating. As a natural domain decomposition method (DDM), in this article, a discontinuous Galerkin (DG) method is proposed to facilitate the steady-state electrical and thermal coanalysis. With the intention to avoid solving a globally coupled steady-state matrix system equations resulted from the implicit numerical flux in DG, the block Thomas method is deployed to solve the entire domain in a subdomain-by-subdomain scheme. As a direct solver, the block …


Spectrum Analyzer-Based Phase Measurement For Near-Field Emi Scanning, Shubhankar Marathe, Zongyi Chen, Kaustav Ghosh, Hamed Kajbaf, Stephan Frei, Morten Sorensen, David Pommerenke, Jin Min Jun 2020

Spectrum Analyzer-Based Phase Measurement For Near-Field Emi Scanning, Shubhankar Marathe, Zongyi Chen, Kaustav Ghosh, Hamed Kajbaf, Stephan Frei, Morten Sorensen, David Pommerenke, Jin Min

Electrical and Computer Engineering Faculty Research & Creative Works

Often, electromagnetic interference (EMI) scanning applications require phase and magnitude information for the creation of equivalent radiation models and far-field predictions. Magnitude information can be obtained using a spectrum analyzer (SA), which is relatively inexpensive compared to phase resolving instruments such as vector network analyzers (VNAs) and oscilloscopes at tens of GHz. This paper introduces and optimizes a cost-effective SA-based phase measurement method and compares the results to a VNA and oscilloscope-based methods for EMI signal sources. The measured-phase distribution obtained from the three different instruments is additionally compared with the simulated phase determined from full-wave simulation. The three measurement …


Optical And Structural Properties Of Nickel Doped Zinc Oxide Grown By Metal Organic Chemical Vapor Deposition (Mocvd) At Different Reaction Chamber Conditions, Zahra Manzoor, Vishal Saravade, Alexis Margaret Corda, Ian Ferguson, Na Lu Jun 2020

Optical And Structural Properties Of Nickel Doped Zinc Oxide Grown By Metal Organic Chemical Vapor Deposition (Mocvd) At Different Reaction Chamber Conditions, Zahra Manzoor, Vishal Saravade, Alexis Margaret Corda, Ian Ferguson, Na Lu

Electrical and Computer Engineering Faculty Research & Creative Works

Metal organic chemical vapor deposition (MOCVD) growth of nickel-doped zinc oxide (Ni-doped ZnO) thin films on sapphire was investigated. The structural and optical properties were studied. The samples were grown at two substrate temperatures (i.e., 450 and 550°C) and at three chamber pressures (22, 30 and 100 Torr). The Ni-doped ZnO samples showed the (002) hexagonal crystal structure with signs of secondary phases in X-ray diffraction (XRD) measurements. However, different XRD peak intensities were observed for these samples at different growth conditions with the same Ni flow rate injection to the reaction chamber. The samples grown at different growth conditions …


Short-Baseline High-Precision Dgps For Smart Snow Blower, Yunlong Luo, Zi Bin Weng, Yihong Qi, Lei Deng, Wei Yu, Fuhai Li, James L. Drewniak, Weihua Zhuang, Miao Miao, Jing Huang Jun 2020

Short-Baseline High-Precision Dgps For Smart Snow Blower, Yunlong Luo, Zi Bin Weng, Yihong Qi, Lei Deng, Wei Yu, Fuhai Li, James L. Drewniak, Weihua Zhuang, Miao Miao, Jing Huang

Electrical and Computer Engineering Faculty Research & Creative Works

High-precision positioning is critical for many Internet-of-Things (IoT) applications; however, most existing approaches are too expensive to be used in commercial products. A highly accurate differential global positioning system (DGPS) has not been widely used because of the difficulty in solving integer ambiguities in the single-frequency carrier phase. Multipath interference and receiver noise are the main reasons for limiting the DGPS accuracy and efficiency in solving integer ambiguities. In this article, we propose a combination of anti-multipath antennas and high-performance GPS receivers to effectively mitigate impairments due to multipath propagation and receiver noise. Furthermore, by exploiting more data available from …


Local Orbital-Angular-Momentum Dependent Surface States With Topological Protection, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha May 2020

Local Orbital-Angular-Momentum Dependent Surface States With Topological Protection, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

Chiral surface states along the zigzag edge of a valley photonic crystal in the honeycomb lattice are demonstrated. By decomposing the local fields into orbital angular momentum (OAM) modes, we find that the chiral surface states present OAM-dependent unidirectional propagation characteristics. Particularly, the propagation directivities of the surface states are quantified by the local OAM decomposition and are found to depend on the chirality's of both the source and surface states. These findings allow for the engineering control of the unidirectional propagation of electromagnetic energy without requiring an ancillary cladding layer. Furthermore, we examine the propagation of the chiral surface …


Investigation Of Honey As The Electrolyte Gate Dielectrics Of Field Effect Transistors, Binghao Wang, Kuan Yew Cheong, Chih Fang Huang, Feng Zhao May 2020

Investigation Of Honey As The Electrolyte Gate Dielectrics Of Field Effect Transistors, Binghao Wang, Kuan Yew Cheong, Chih Fang Huang, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

The paper reports on the investigation of honey as the electrolyte gate dielectrics of graphene field effect transistors. Transfer and output characteristics of graphene transistors were collected at room temperature and 40 °C under open air. Typical behaviors such as Dirac neutrality point and linear relation of drain current with drain-source voltage at low field and various gate bias voltages were achieved. In addition, cleaning and reapplication of honey on transistors only show slight changes in those characteristics.


Microwave Nondestructive Detection Of Influenc Of Alkali-Silica Reaction (Asr) In Materials Properties Of Concrete Specimens, Reza Zoughi, John R. Gallion, Nolan W. Hayes May 2020

Microwave Nondestructive Detection Of Influenc Of Alkali-Silica Reaction (Asr) In Materials Properties Of Concrete Specimens, Reza Zoughi, John R. Gallion, Nolan W. Hayes

Electrical and Computer Engineering Faculty Research & Creative Works

Alkali-silica reaction has been identified to be a cause deterioration in concrete structures. This reaction takes place when alkalis (e.g., potassium and sodium), hydroxyl ions in the pore solution and certain siliceous minerals (present in some aggregates) are present, resulting in what is known as the ASR gel. Expansion of this gel, in the presence of heat and moisture, causes stresses that lead to microcracking and deterioration of concrete. The criticality of this problem has been particularly highlighted in recent past with respect to nuclear power plant containment concrete structures. Although there have been many studies devoted to examining and …


Impact Of Large-Scale Correlated Failures On Multilevel Virtualized Networks, Max G. Medina, Mohammed J.F. Alenazi, Egemen K. Cetinkaya May 2020

Impact Of Large-Scale Correlated Failures On Multilevel Virtualized Networks, Max G. Medina, Mohammed J.F. Alenazi, Egemen K. Cetinkaya

Electrical and Computer Engineering Faculty Research & Creative Works

Communication network architectures have been evolving with increased programmability and virtualization of physical infrastructures. While this evolution enables a faster introduction of new services and efficient utilization of resources, the complexities and interdependencies among the physical and virtual infrastructures, as well as the control and management planes, hinder a complete understanding of the system at hand. It is imperative, therefore, to model and study these evolving virtualized infrastructures. We propose a multilevel virtualized network embedding model and study its performance against correlated failures. Our analysis of multiple synthetic network models identified that grid-like infrastructures capture the realistic Internet2 structure the …


Low Leakage Gan Hemts With Sub-100 Nm T-Shape Gates Fabricated By A Low-Damage Etching Process, Siqi Lei, Wei Chih Cheng, Jingyi Wu, Liang Wang, Qing Wang, Guangrui Xia, Feng Zhao, Hongyu Yu Apr 2020

Low Leakage Gan Hemts With Sub-100 Nm T-Shape Gates Fabricated By A Low-Damage Etching Process, Siqi Lei, Wei Chih Cheng, Jingyi Wu, Liang Wang, Qing Wang, Guangrui Xia, Feng Zhao, Hongyu Yu

Electrical and Computer Engineering Faculty Research & Creative Works

This paper demonstrates a new fabrication process for gallium nitride high-electron mobility transistors (HEMTs) free of plasma damages in the sub-100 nm T-shape gate area. The common peeling-off problems of electron beam resists during gate metal deposition process were solved by introducing a fluorine plasma treatment process before gate metal deposition. By combining dry and wet etching processes appropriately, an on/off ratio of 107 at a drain-to-source voltage of 1 V was achieved. This work also investigated the short channel effect in devices with gate lengths from 70 to 440 nm. Reducing gate length results in decrease of threshold …


Numerical Study Of 4h-Sic Umosfets With Split-Gate And P+ Shielding, Jheng Yi Jiang, Tian Li Wu, Feng Zhao, Chih Fang Huang Mar 2020

Numerical Study Of 4h-Sic Umosfets With Split-Gate And P+ Shielding, Jheng Yi Jiang, Tian Li Wu, Feng Zhao, Chih Fang Huang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, performances of a 4H-SiC UMOSFET with split gate and P+ shielding in different configurations are simulated and compared, with an emphasis on the switching characteristics and short circuit capability. A novel structure with the split gate in touch with the P+ shielding is proposed. The key design issues for 4H-SiC UMOSFETs are trench gate dielectric protection and reverse transfer capacitance Crss reduction. Based on simulation results, it is concluded that a UMOSFET with a gate structure combining split gate grounded to the trench bottom protection P+ shielding layer and a current spreading layer is achieved to yield …


Distributed Adaptive State Estimation And Tracking By Using Active-Passive Sensor Networks, Akhilesh Raj, Sarangapani Jagannathan, Tansel Yucelen Mar 2020

Distributed Adaptive State Estimation And Tracking By Using Active-Passive Sensor Networks, Akhilesh Raj, Sarangapani Jagannathan, Tansel Yucelen

Electrical and Computer Engineering Faculty Research & Creative Works

Heterogeneous sensor networks (HSN) find a wide range of applications in the field of military and civilian environments, where sensor nodes are utilized to estimate the position of a target with both dynamics and control input being unknown for the purposes of tracking. In the HSN, nodes are considered active depending upon their ability to sense the target output while the others are taken passive. Accurate estimation requires local information exchange among the spatially located sensor nodes, so that the active nodes as well as the passive nodes converge simultaneously to the same value. The local information exchange among the …


The Voltage Regulation Of A Buck Converter Using A Neural Network Predictive Controller, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi Feb 2020

The Voltage Regulation Of A Buck Converter Using A Neural Network Predictive Controller, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a neural network predictive controller (NNPC) is proposed to control a buck converter. Conventional controllers such as proportional-integral (PI) or proportional-integral-derivative (PID) are designed based on the linearized small-signal model near the operating point. Therefore, the performance of the controller in the start-up, load change, or reference change is not optimal since the system model changes by changing the operating point. The neural network predictive controller optimally controls the buck converter by following the concept of the traditional model predictive controller. The advantage of the NNPC is that the neural network system identification decreases the inaccuracy of …


The Heuristic Dynamic Programming Approach In Boost Converters, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi Feb 2020

The Heuristic Dynamic Programming Approach In Boost Converters, Sepehr Saadatmand, Pourya Shamsi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In this study, a heuristic dynamic programming controller is proposed to control a boost converter. Conventional controllers such as proportional-integral-derivative (PID) or proportional-integral (PI) are designed based on the linearized small-signal model near the operating point. Therefore, the performance of the controller during the start-up, the load change, or the input voltage variation is not optimal since the system model changes by varying the operating point. The heuristic dynamic programming controller optimally controls the boost converter by following the approximate dynamic programming. The advantage of the HDP is that the neural network-based characteristic of the proposed controller enables boost converters …