Digital Commons Network^™

1-Bit Compressed Sensing Based Framework For Built-In Resonance Frequency Prediction Using On-Chip Noise Sensors, Tao Wang, Jinglan Liu, Cheng Zhuo, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Significant noise will occur when the load currents of a chip contain frequency components that are close to its resonance frequency, which is mainly decided by power delivery network (PDN) capacitance and package inductance. Yet with technology scaling, the wire parasitic capacitance, which suffers from large process variations, starts to become a dominant contributor in the PDN capacitance, leading to a large resonance frequency variation across dies. It is thus important to know the resonance frequency of individual chips to effectively avoid resonance noise at runtime. Existing methods are mostly based on frequency sweeping, which are too expensive to apply …

Effects Of Electrode Materials On Charge Conduction Mechanisms Of Memory Device Based On Natural Aloe Vera, Zhe Xi Lim, Sasidharan Sreenivasan, Yew Hoong Wong, Feng Zhao, Kuan Yew Cheong

Electrical and Computer Engineering Faculty Research & Creative Works

Resistive switching behaviors in Aloe vera films are being explored for nonvolatile memory applications. A simple structure in which the Aloe vera films sandwiched in between a top and bottom electrode are used. The switching behaviors of the devices in which the Aloe vera film is dried at different temperatures and the roles of top electrode materials (Al and Ag) are investigated. Current density-voltage measurements reveal that filamentary conduction is the dominant conduction process inducing resistive switching characteristics in Aloe vera films. Device with Al-Top electrode requires a forming voltage higher than devices with Ag-Top electrode, due to the tendency …

Transient Analysis Of Lumped Circuit Networks-Loaded Thin Wires By Dgtd Method, P. Li, Y. Shi, Lijun Jiang, H. Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

With the purpose of avoiding very fine mesh cells in the proximity of a thin wire, the modified telegrapher’s equations (MTEs) are employed to describe the thin wire voltage and current distributions, which consequently results in reduced number of unknowns and augmented Courant–Friedrichs–Lewy (CFL) number. As hyperbolic systems, both the MTEs and the Maxwell’s equations are solved by the discontinuous Galerkin time-domain (DGTD) method. In realistic situations, the thin wires could be either driven or loaded by circuit networks. The thin wire–circuit interface performs as a boundary condition for the thin wire solver, where the thin wire voltage and current …

A Novel Relaxed Hierarchical Equivalent Source Algorithm (Rhesa) For Electromagnetic Scattering Analysis Of Dielectric Objects, Xin Fu, Li (Lijun) Jun Jiang, Hong Tat Ewe

Electrical and Computer Engineering Faculty Research & Creative Works

A novel relaxed hierarchical algorithm based on the surface equivalence principle for the volume integral equations (VIEs) is proposed in this work. The equivalent sources residing on relaxed spherical equivalence surfaces are established by exact integral formulations. The equivalence surfaces are exploited hierarchically to accelerate matrix–vector product in iterative solutions for the VIEs. The computation time and memory cost complexity of the proposed algorithm for dielectric scatters scale as O(N4/3) and O(N) , respectively. Numerical examples validate the accuracy and capability of the proposed algorithm.

Performance Enhancement Of Equivalence Principle Algorithm, Xin Fu, Li (Lijun) Jun Jiang, Zu Hui Ma, Shi Quan He

Electrical and Computer Engineering Faculty Research & Creative Works

The conventional equivalence principle algorithm (EPA) exploits cubical surfaces to support equivalent sources. However, it introduces strong discontinuities due to sharp edges and corners. In this letter, a spherical surface is employed as the equivalence surface to avoid singularities from nonsmoothness. To achieve better accuracy, the meshless sampling scheme is used for integral operators on the spherical equivalence surface. The numerical examples are provided to validate the performance enhancement of EPA through the proposed method.

Stress-Induced Birefringence And Fabrication Of In-Fiber Polarization Devices By Controlled Femtosecond Laser Irradiations, Lei Yuan, Baokai Cheng, Jie Huang, Jie Liu, Hanzheng Wang, Xinwei Lan, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Optical birefringence was created in a single-mode fiber by introducing a series of symmetric cuboid stress rods on both sides of the fiber core along the fiber axis using a femtosecond laser. The stress-induced birefringence was estimated to be 2.4 x 10^-4 at the wavelength of 1550 nm. By adding the desired numbers of stressed rods, an in-fiber quarter waveplate was fabricated with a insertion loss of 0.19 dB. The stressinduced birefringence was further explored to fabricate in-fiber polarizers based on the polarization-dependent long-period fiber grating (LPFG) structure. A polarization extinction ratio of more than 20 dB was observed …

Co-Doping Of Magnesium With Indium In Nitrides: First Principle Calculation And Experiment, Zhiqiang Liu, Binglei Fu, Xiaoyan Yi, Guodong Yuan, Junxi Wang, Jinmin Li, Luna, Ian Ferguson

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, an effective strategy for achieving efficient p-type doping in wide bandgap nitride semiconductors was proposed to overcome the fundamental issue of high activation energy. We demonstrated that a hole concentration as high as 1.4 x 1018 cm-3 could been achieved through In-Mg co-doping. The electronic structure of the system and the formation energy of impurity were analyzed via first principal calculation to clarify the underlying physics and the ambiguity in understanding of the origin of the high hole concentration. Our results indicated that the original valence band maximum of the host materials could be modified, thus improving …

Mitigation Emission Strategy Based On Resonances From A Power Inverter System In Electric Vehicles, L. Zhai, Xinyu Zhang, Natalia G. Bondarenko, David Loken, Thomas Van Doren, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

Large dv/dt and di/dt outputs of power devices in the DC-fed motor power inverter can generate conducted and/or radiated emissions through parasitics that interfere with low voltage electric systems in electric vehicles (EVs) and nearby vehicles. The electromagnetic interference (EMI) filters, ferrite chokes, and shielding added in the product process based on the "black box" approach can reduce the emission levels in a specific frequency range. However, these countermeasures may also introduce an unexpected increase in EMI noises in other frequency ranges due to added capacitances and inductances in filters resonating with elements of the power inverter, and even increase …

Pre-College Engineering Activities With Electronic Circuits (Work-In-Progress), Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

Projects involving engineering experimentation, design, and measurement can be effective content for pre-college STEM outreach. Such applications-oriented activities can promote literacy and interest in technical topics and careers and have the added benefit of showing the relevance of science and mathematics. Exposure to electrical engineering concepts is discussed using the 555 timer integrated circuit. This low-cost device can be used for modular activities involving the production of light, sound, and motion. Specific projects are presented that are appropriate for pre-college students from 9th-grade through 12th-grade.

Electrostatically-Actuated 4h-Sic In-Plane And Out-Of-Plane High Frequency Mems Resonator, Allen V. Lim, Tutku Karacolak, Jheng Yi Jiang, Chih Fang Huang, Feng Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

As a wide bandgap and single crystalline semiconductor, 4H-polytype silicon carbide (4H-SiC) is an excellent material choice for devices operating in harsh environments of high temperature, high pressure, radiation, chemical and biomedical, etc. In this letter, an electrostatically actuated 4H-SiC micro resonator was fabricated by dopant-selective photoelectrochemical etching of n-p-n homoepitaxial structure. Resonant frequencies of 3.463 MHz (out-of-plane) and 16.9 MHz (in-plane) were attained, and they are in good agreement with theoretical calculation. To the best of our knowledge, these frequencies are the highest values ever reported from single crystalline 4H-SiC MEMS resonators.

Novel Time Domain Integral Equation Method Hybridized With The Macromodels Of Circuits, Huan Huan Zhang, He Ming Yao, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents a novel transient field-circuit simulation method based on the time-domain integral equation (TDIE) and circuit macromodels. The traditional field-circuit simulation method constructs the Kirchoff's equations for lumped circuits with SPICE models, but they cannot handle problems with unknown circuit structures. The proposed method creates parametric macromodels to represent the port constitutive relations of the unknown circuits. Then the obtained macromodel is coupled with TDIE to enable the transient field-circuit cosimulation. Numerical examples are given to demonstrate the validity of the proposed method. The proposed method is targeted to solve unknown I/O modeling issues in general signal integrity …

Broadband High Gain Siw Ring Slot Antenna, Zhi Shen, Kirti Dhwaj, Hanseung Lee, Tatsuo Itoh, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The slot antenna backed by the substrate integrated waveguide (SIW) cavity usually demonstrates very narrow bandwidth. In this paper, we extend the interpretation to our original dual mode SIW ring slot antenna so that a broadband radiation property based on the TE102 mode is unveiled for the first time. Through the experimental verification, over 12% bandwidth is conveniently achieved. The realized gain reaches over 7 dB. Its broadband working principle is studied in details. Simulated and measured data are both presented to verify the proposed ideas.

A Low Complexity Reweighted Proportionate Affine Projection Algorithm With Memory And Row Action Projection, Jianming Liu, Steven L. Grant, Jacob Benesty

Electrical and Computer Engineering Faculty Research & Creative Works

A new reweighted proportionate affine projection algorithm (RPAPA) with memory and row action projection (MRAP) is proposed in this paper. The reweighted PAPA is derived from a family of sparseness measures, which demonstrate performance similar to mu-law and the l0 norm PAPA but with lower computational complexity. The sparseness of the channel is taken into account to improve the performance for dispersive system identification. Meanwhile, the memory of the filter's coefficients is combined with row action projections (RAP) to significantly reduce computational complexity. Simulation results demonstrate that the proposed RPAPA MRAP algorithm outperforms both the affine projection algorithm (APA) and …

An Overview On Optimized Nlms Algorithms For Acoustic Echo Cancellation, Constantin Paleologu, Silviu Ciochină, Jacob Benesty, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

Acoustic echo cancellation represents one of the most challenging system identification problems. The most used adaptive filter in this application is the popular normalized least mean square (NLMS) algorithm, which has to address the classical compromise between fast convergence/tracking and low mis adjustment. In order to meet these conflicting requirements, the step-size of this algorithm needs to be controlled. Inspired by the pioneering work of Prof. E. Hänsler and his collaborators on this fundamental topic, we present in this paper several solutions to control the adaptation of the NLMS adaptive filter. The developed algorithms are "non-parametric" in nature, i.e., they …

Fast Random Walk Based Capacitance Extraction For The 3-D Ic Structures With Cylindrical Inter-Tier-Vias, Chao Zhang, Wenjian Yu, Qing Wang, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

3-D integrated circuits (3-D ICs) make use of the vertical dimension for smaller footprint, higher speed, lower power consumption, and better timing performance. In 3-D ICs, the inter-Tier-via (ITV) is a critical enabling technique because it forms vertical signal and power paths. Accordingly, it is imperative to accurately and efficiently extract the electrostatic capacitances of ITVs using field solvers. Unfortunately, the cylindrical via shape presents major challenges to most of the existing methods. To address this issue, we develop a novel floating random walk (FRW) method by rotating the transition cube to suit the cylindrical surface, devising a special space …

Dgtd Analysis Of Electromagnetic Scattering From Penetrable Conductive Objects With Ibc, Ping Li, Yifei Shi, Li (Lijun) Jun Jiang, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

To avoid straightforward volumetric discretization, a discontinuous Galerkin time-domain (DGTD) method integrated with the impedance boundary condition (IBC) is presented in this paper to analyze the scattering from objects with finite conductivity. Two situations are considered. 1) The skin depth is smaller than the thickness of the conductive volume. 2) The skin depth is larger than the thickness of a thin conductive sheet. For the first situation, a surface impedance boundary condition (SIBC) is employed, wherein the surface impedance usually exhibits a complex relation with the frequency. To incorporate the SIBC into DGTD, the surface impedance is first approximated by …

Manipulating Electromagnetic Local Density Of States By Graphene Plasmonics, Yongpin P. Chen, Wei E.I. Sha, Li (Lijun) Jun Jiang, Jun Hu

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic local density of states (ELDOS) counts the number of electromagnetic modes at a spatial point where a particle (atom, molecule, and quantum dot) spontaneously emits electromagnetic waves. ELDOS can be interpreted as a density of vacuum fluctuations of electromagnetic fields. Moreover, ELDOS is essential to control spontaneous decay rate (SDR) of particles; and thus plays a critical role in modern optical and quantum devices. Having a great degree of freedom to tune permittivity, graphene is an emerging building block to manipulate the ELDOS. In this work, we study SDR of a particle near a metallic split-ring resonator, which is …

Capillary Wall Coupled Whispering Gallery Mode Microresonator, Hai Xiao, Wang Hanzheng

Electrical and Computer Engineering Faculty Research & Creative Works

A microresonator structure comprises a waveguide and a microsphere. The waveguide is of elongated cylindrical shape and includes a first section of optical transmission material and a cavity section axially aligned with the first section. The cavity section includes a first cavity and a second cavity. The first cavity is adjacent to the first section and includes a first sidewall of optical transmission material with an inner surface that tapers inward to an apex positioned adjacent to the first section. The second cavity is positioned adjacent to the first cavity of hollow cylindrical shape and includes a circumferential second sidewall …

Real-Time Supervised Detection Of Pink Areas In Dermoscopic Images Of Melanoma: Importance Of Color Shades, Texture And Location, Ravneet Kaur, P. P. Albano, Justin G. Cole, Jason R. Hagerty, Robert W. Leander, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

Background/Purpose: Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits.

Methods: Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue, and saturation). Color shade analysis was performed using a logistic …

Electromagnetic Characterization For Graphene By The Peec Method, Ying S. Cao, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The electromagnetic (EM) features of graphene are characterized by the partial element equivalent circuit (PEEC) model for the first time with an impedance boundary condition. By incorporating the impedance boundary condition into the PEEC model, a novel surface conductivity circuit is proposed for graphene. Furthermore, the definition of the absorption cross section (σabs) and the scattering cross section (σsca) are revisited to make them feasible for PEEC analysis. The application of the impedance boundary condition significantly alleviates the memory consumption and the CPU time. To validate the proposed algorithm, numerical examples are presented and compared with existing references.

Hierarchical Equivalent Source Algorithm Based On Relaxed Spherical Equivalence Surface, Xin Fu, Li (Lijun) Jun Jiang, Hong Tat Ewe

Electrical and Computer Engineering Faculty Research & Creative Works

A new hierarchical algorithm based on surface equivalence principle is proposed in this work. The equivalent sources residing on relaxed spherical equivalence surfaces are computed by closed-form integral operators rather than numerical approximations. Consequently, a hierarchical algorithm based on oct-tree is straightforward to implement. Numerical examples validate the accuracy and capability of the proposed algorithm.

A Supercell Based Dual Beam Dielectric Grating Antenna For 60 Ghz Application, Zi Long Ma, Chi Hou Chan, Kung Bo Ng, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

A dual-beam dielectric grating antenna based on the supercell (SC) concept is presented in this paper. Theoretical analysis shows that with the perturbations of different unit cells (UC), two space harmonic modes (m = -1 and m = -2) are excited (above the air line) in the dispersion diagram of the supercell in a certain frequency range. This phenomenon leads to the generation of two radiation beams in the far-field region. At the operating frequency where the phase constants β-1 =β in symmetric directions. In addition, a symmetric SC is proposed and carefully designed to achieve equal performance (beam width …

Calculating The Scattered Fields From The Fock Currents Of The 3-D Convex Scatterers By The Incremental Length Diffraction Technique, Yu Mao Wu, Weng Cho Chew, Tie Jun Cui, Ya Qiu Jin, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, we consider the accuracy improvement of the high frequency scattered fields from the 3-D convex scatterers with the aid of the Fock current and the incremental length diffraction coefficient (ILDC) technique. To efficiently calculate the Fock currents, we adopt the numerical contour deformation method. Then, by using the Fock currents and the ILDC technique, high frequency scattered fields are clearly formulated. Compared to the PO scattered fields from the 3-D convex sphere, numerical results demonstrate significant accuracy enhancement of the scattered field via the Fock current.

Modeling Of Magnetized Graphene From Microwave To Thz Range By Dgtd With A Scalar Rbc And An Ade, Ping Li, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a discontinuous Galerkin timedomain (DGTD) method for the transient analysis of magnetized graphene from the microwave to terahertz (THz) frequencies. By considering the atom thick graphene layer as an infinitely thin conductive sheet with finite surface conductivity, a frequency-dependent anisotropic resistive boundary condition (RBC) is obtained. Based on this RBC, the direct volumetric discretization of graphene layer is avoided. Instead of directly deriving the numerical flux for DGTD considering the presence of this anisotropic and dispersive RBC, an auxiliary surface polarization current governed by a first-order time-dependent partial differential equation (PDE) is introduced over the graphene with …

Nonlinear Acoustic Echo Cancellation Using Voltage And Current Feedback, Pratik Shah, Ian Lewis, Steven Grant, Sylvain Angrignon

Electrical and Computer Engineering Faculty Research & Creative Works

Acoustic echo cancellation (AEC) is a well-studied problem. The underlying assumption in most echo cancellation solutions is that the echo path following the reference signal is completely linear. However, in many handheld devices, the echo path following the reference signal is nonlinear. The reason for this nonlinearity in the echo path is the use of smaller inexpensive loudspeakers and the desire for generating high sound pressure levels. This brings about the need for a nonlinear echo canceler to maintain the required echo return loss enhancement (ERLE). Many software-based solutions have been proposed to solve this problem, but the computational complexity …

Wiretap Channel Ii With A Noisy Main Channel, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a wiretap channel where the transmitter and receiver communicate through a discrete memoryless channel, and the eavesdropper (Eve) has perfect access to a fixed fraction of transmitted symbols (of its choosing) is considered. An outer bound for the rate-equivocation region of the channel, for all such fractions, is derived. An achievable scheme, which provides an inner bound for the rate-equivocation region, is proposed. The achievability is established by defining a class of good codebooks for which there exists a good partition that achieves the required level of equivocation no matter what subset of symbols Eve chooses. It …

Introduction To: Special Issue On Cross-Layer System Design, Yiyu Shi, Takashi Sato

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Using Simulation & Joint Time/Frequency Domain Analysis To Evaluate Absorber/Lossy Material Performance In Resonant Cavities, Bruce Archambeault, Michael Varner, Jiawei Zhang, Sam Connor, Edward Wheeler

Electrical and Computer Engineering Faculty Research & Creative Works

Comparing the effectiveness of different absorber/lossy materials as a function of frequency can be difficult and prone to misunderstanding when the reduction in field strength is observed directly. Often these materials are used in highly resonant cavities, therefore a better measure of the reduction of field strength is the resonant quality factor (Q-factor). The Joint Time-Frequency domain analysis technique allows simulation data from time domain simulations to be easily converted to Q-factor and allows quick and straightforward analysis of the improvement gained by using various absorber/lossy materials. Measurements are made to validate the simulation results.

Secure Degrees Of Freedom Of N ×N ×M Wiretap Channel With A K-Antenna Cooperative Jammer, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

The secure degrees of freedom (s.d.o.f.) of a multiantenna Gaussian wiretap channel with N antennas at the transmitter and receiver and an arbitrary number of antennas, M, at the wiretapper is characterized when a multiantenna cooperative jammer (CJ) is available as a helper. This generalizes our previous result that assumed the same number of antennas at the eavesdropper as the legitimate parties. In particular, for arbitrary values of N and M, the s.d.o.f. is derived for all possible values of the number of antennae at the CJ, K. The achievability is based on a variety of signaling, beamforming, and alignment …

Secure Massive Mimo Transmission In The Presence Of 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 (MIMO) systems in the presence of an 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 towards the eavesdropper, thus increasing its received signal power. We derive an asymptotic achievable secrecy rate for matched filter precoding and artificial noise (AN) generation at the transmitter when the number of transmit …