Engineering Commons^™

Conductive Concrete For Electromagnetic Shielding – Methods For Development And Evaluation, Aaron P. Krause

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This research investigates the development and evaluation innovative methods for the use of conductive concrete as an electromagnetic shield. New testing methods are developed to determine the best conductive components to use in the design of a concrete mixture for shielding that shows the best promise. The conductive concrete mixture has the potential to provide electromagnetic shielding that is cost-effective in terms of construction, operation, and maintenance compared to conventional approaches. Two testing methods, Small Sample Testing and Large Slab Testing, are developed based on standardized testing methods that have been modified for the testing of conductive concrete mixtures. As …

Circularly Polarized Terminal Antennas For Emerging Wireless Systems, Max Ammann, Xiulong Bao, Adam Narbudowicz

Conference Papers

Several types of omni-directional Circularly Polarized (CP) antennas are presented, which are employed by three different types of feedlines: Coplanar Waveguide (CPW) fed, Microstrip fed, and Differential-fed, to achieve omni-directional CP performances. The Dual-frequency Omni-directional CP antenna is proposed by using slot and inductor embedded into radiated patches. These omnidirectional CP antennas have potential application on GPS, WLAN and RFID systems.

A 2.45/5.8 Ghz Folded Monopole Antenna For Wlan Applications, Abraham Loutridis, Matthias John, Giuseppe Ruvio, Max Ammann

Conference Papers

A probe-fed printed folded monopole antenna for WLAN applications is presented. The antenna operates at 2.45 GHz and 5.8 GHz, is compact and has omni-directional characteristics in both bands. A parametric study of key geometrical parameters is reported.

Integration Of Inverted-F Antenna With Solar Cell Substitute, Oisin O’Conchubhair, Patrick Mcevoy, Max Ammann, Giuseppe Ruvio

Conference Papers

A study into the effect of a solar cell lattice on the performance of an Inverted-F antenna is presented. An FR-4 substrate with a lattice of copper electrodes printed on one side and a solid copper ground plane on the other is used to represent a polycrystalline solar cell. The effect of the lattice orientation on the performance of the Inverted-F antenna is discussed.

Wireless Networks-On-Chips: Architecture, Wireless Channel, And Devices, David W. Matolak, Avinash Kodi, Savas Kaya, Dominic Ditomaso, Soumyasanta Laha, William Rayess

Faculty Publications

Wireless networks-on-chips (WINoCs) hold substantial promise for enhancing multicore integrated circuit performance, by augmenting conventional wired interconnects. As the number of cores per IC grows, intercore communication requirements will also grow, and WINoCs can be used to both save power and reduce latency. In this article, we briefly describe some of the key challenges with WINoC implementation, and also describe our example design, iWISE, which is a scalable wireless interconnect design. We show that the integration of wireless interconnects with wired interconnects in NoCs can reduce overall network power by 34 percent while achieving a speedup of 2.54 on real …

On The Fundamentals Of Stochastic Spatial Modeling And Analysis Of Wireless Networks And Its Impact To Channel Losses, Mouhamed Abdulla

Publications and Scholarship

With the rapid evolution of wireless networking, it becomes vital to ensure transmission reliability, enhanced connectivity, and efficient resource utilization. One possible pathway for gaining insight into these critical requirements would be to explore the spatial geometry of the network. However, tractably characterizing the actual position of nodes for large wireless networks (LWNs) is technically unfeasible. Thus, stochastical spatial modeling is commonly considered for emulating the random pattern of mobile users. As a result, the concept of random geometry is gaining attention in the field of cellular systems in order to analytically extract hidden features and properties useful for assessing …

Proximity Study Of A Uwb Directional Conformal Antenna On Water Pipe, Domenico Gaetano, Max Ammann, Patrick Mcevoy, Matthias John, Louise Keating, Frances Horgan

Articles

A preliminary study on the conformal properties of an antipodal exponentially tapered antenna placed on the surface of a flow meter system in the UWB range is presented. It was observed that the water effect can be mitigated by shifting the antenna away from the pipe surface.

Spectral Analysis Of Encrypted Chaotic Signals Using Fast Fourier Transforms And Laboratory Spectral Analyzers, Monish Ranjan Chatterjee, Abhinay Kundur

Electrical and Computer Engineering Faculty Publications

The use of acousto-optic chaos, as manifested via first-order feedback in an acousto-optic Bragg cell, in encrypting a message wave and subsequently recovering the message in the receiver using a chaotic heterodyne strategy, has been reported recently [1-3]. In examining the dynamical system analytically using computer simulation, (expected) modulated chaos waveforms are obtained within specified observation windows.

Because of the relatively random nature inherent in chaos waveforms, it is essentially impossible to ascertain from the visual display of the chaotic wave whether a given message signal has in fact modulated the chaotic "carrier". In fact, it has been observed from …

Energy Efficiency Analysis And Optimization On Mobile Video Wireless Delivery, Jianxin Sun

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Micro-electronic industry has been boosting the capability of wireless mobile devices on full-scale. However, battery, as the only power source of most mobile devices, is experiencing a relatively slow development. Therefore, how to optimally utilize the limited battery energy on mobile devices under a predefined performance requirement becomes a critical issue. On the other hand, it is still unclear that how the battery capacity consumption is allocated on different working pattern of a specific video codec under various tempo-spatial scales and parameters, which has posed a design challenge on power management on multimedia communication system. Furthermore, an optimization method is …

Vivaldi Array For Generation Of Uwb Circular Polarization, Adam Narbudowicz, Matthias John, Xiulong Bao, Max Ammann

Conference Papers

A two antenna array is proposed for generating circular polarization for an ultra-wideband system. It consists of two orthogonal antipodal vivaldi antennas and a feed network which provides the appropriate phase and amplitude over the band of interest. The proposed structure is low cost and easy to manufacture, offering an axial-ratio bandwidth of 74%.

An Enhanced Method To Measure Pulse Dispersion In Uwb Antennas, Antoine Dumoulin, Matthias John, Patrick Mcevoy, Max Ammann

Conference Papers

This paper will demonstrate a method to remove the dispersive effects of antennas and measurement equipment from a real time-domain measurement setup. By isolating the AUT transfer function, more accurate time-domain measurements can be achieved and agreement to simulation improved.

Optimized Monopole And Dipole Antennas For Uwb Asset Tag Location Systems, Antoine Dumoulin, Matthias John, Max Ammann, Patrick Mcevoy

Articles

Miniaturized monopole and dipole antenna designs are reported with performances optimized for ultrawideband pulsed radio applications. The geometries are created using Bézier spline shapes, which have been refined with a genetic algorithm to simultaneously take account of both frequency- and time-domain criteria. Time-domain measurements of ultra wideband antennas with uniformly distributed energy across the full 3.1-10.6 GHz mask are reported for the first time and validate a new approach to minimization of pulse dispersion effects in the antenna designs.

A Multi-Modal Sensing And Communication Platform For Continental-Scale Migratory Bird Tracking, David J. Anthony

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This thesis presents a novel platform for tracking migratory birds on a continental scale. Cellular technology is used to augment the short-range radios that have traditionally been used in wireless sensor networks. The platform utilizes multiple sensors, including a GPS and solid state compass. By using these sensors, the platform is capable of not only tracking a bird’s migration path, but also provides information on a bird’s behavior during its life-cycle. Testing methodology utilizing simulations and aspect-oriented programming is used to reveal faults in the platform prior to deployment on wild animals. In collaboration with the International Crane Foundation, and …

Wireless Communications Under Qos Constraints: Energy Efficiency, Power And Rate Control, And Throughput, Deli Qiao

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This dissertation deals with various issues in wireless communications under statistical quality of service (QoS) constraints. Effective capacity, which provides the maximum constant arrival rate that a wireless channel can sustain while satisfying statistical QoS constraints, is adopted as the performance metric. Energy efficiency of point-to-point links is first studied by characterizing the spectral efficiency-bit energy tradeoff in the low-power and wideband regimes. Different transmission strategies (with variable or fixed rate) and power policies are studied. Then, the effective capacity region for fading multiple-access channels (MAC) is investigated for different transmission strategies: Superposition coding with successive decoding and time division …

Dynamical Model Of Harmonic Generation In Centrosymmetric Semiconductors At Visible And Uv Wavelengths, Michael Scalora, Maria Antonietta Vincenti, Domenico De Ceglia, N. Akozbek, Vito Roppo, M. J. Bloemer, Joseph W. Haus

Electrical and Computer Engineering Faculty Publications

We study second and third harmonic generation in centrosymmetric semiconductors at visible and UV wavelengths in bulk and cavity environments. Second harmonic generation is due to a combination of spatial symmetry breaking, the magnetic portion of the Lorentz force, and quadrupolar contributions from inner core electrons. The material is assumed to have a nonzero, third-order nonlinearity that gives rise to most of the third harmonic signal. Using the parameters of bulk silicon we predict that cavity environments modify the dependence of second harmonic generation on incident angle, while improving third harmonic conversion efficiency by several orders of magnitude relative to …

Information Encryption And Retrieval In Mid-Rf Range Using Acousto-Optic Chaos, Monish Ranjan Chatterjee, Abhinay Kundur

Electrical and Computer Engineering Faculty Publications

In recent work, low-frequency AC signal encryption, decryption and retrieval using system-parameter based keys at the receiver stage of an acousto-optic (A-O) Bragg cell under first-order feedback have been demonstrated [1,2]. The corresponding nonlinear dynamics have also been investigated using the Lyapunov exponent and the so-called bifurcation maps [3]. The results were essentially restricted to A-O chaos around 10 KHz, and (baseband) signal bandwidths in the 1-4 KHz range. The results have generally been satisfactory, and parameter tolerances (prior to severe signal distortion at the output) in the ±5% - ±10% range have been obtained.

Periodic AC waveforms, and a …

Optimised Tapered-Slot Antenna For Real Time Location Systems, Antoine Dumoulin, Matthias John, Patrick Mcevoy, Max Ammann

Conference Papers

The design of a directional UWB tapered slot antenna for use within an asset tracking system is reported. The spline-based geometry was refined with a local optimization algorithm and a square root raised cosine pulse. The time-domain performance of the antenna is dependent on the optimisation method.

A Microfiber Coupler Tip Thermometer, Ming Ding, Pengfei Wang, Gilberto Bramilla

Articles

A compact thermometer based on a broadband microfiber coupler tip is demonstrated. This sensor can measure a broad temperature interval ranging from room temperature to 1283 degrees C with sub-200 mu m spatial resolution. An average sensitivity of 11.96 pm/degrees C was achieved for a coupler tip with similar to 2.5 mu m diameter. This is the highest temperature measured with a silica optical fiber device. (C)2012 Optical Society of America

Evanescent Field Coupling Between Two Parallel Close Contact Sms Fiber Structures, Qiang Wu, Youqiao Ma, Jinhui Yuan, Yuliya Semenova, Pengfei Wang, Chongxiu Yu, Gerald Farrell

Articles

We proposed a novel optical coupling technique based on two parallel singlemode-multimode- singlemode (SMS) fiber structures. This technique utilizes one SMS structure to excite multiple cladding modes within an output singlemode fiber. The excited multiple cladding modes will be coupled to the input SMF in the second SMS structure by placing the two SMS fiber structures in parallel and in close contact each other. The coupled cladding modes will be re-coupled to a guided core mode by the second SMS fiber structure. Theoretical analysis for such technique was provided and experimentally we have achieved a pass band spectral response with …

Benchmarking Virtual Network Mapping Algorithms, Jin Zhu

Masters Theses 1911 - February 2014

The network architecture of the current Internet cannot accommodate the deployment of novel network-layer protocols. To address this fundamental problem, network virtualization has been proposed, where a single physical infrastructure is shared among different virtual network slices. A key operational problem in network virtualization is the need to allocate physical node and link resources to virtual network requests. While several different virtual network mapping algorithms have been proposed in literature, it is difficult to compare their performance due to differences in the evaluation methods used. In this thesis work, we proposed VNMBench, a virtual network mapping benchmark that provides a …

Germanium Microsphere High-Q Resonator, Pengfei Wang, Timothy Lee, Ming Ding, Anirban Dhar, Thomas Hawkins, Paul Foy, Yuliya Semenova, Qiang Wu, Jayanta Sahu, Gerald Farrell, John Ballato, Gilberto Brambilla

Articles

In this Letter, the fabrication and characterization of a microsphere resonator from the semiconductor germanium is demonstrated. Whispering gallery modes are excited in a 46 μm diameter germanium microsphere resonator using evanescent coupling from a tapered silica optical fiber with a waist diameter of 2 μm. Resonances with Q factors as high as 3.8×104 at wavelengths near 2 μm are observed. Because of their ultrahigh optical nonlinearities and extremely broad transparency window, germanium microsphere resonators offer the potential for optical processing devices, in particular at long wavelengths, such as around 2 μm.

A Threshold-Based Approach To Calorimetry In Helium Droplets: Measurement Of Binding Energies Of Water Clusters, William K. Lewis, Barbara A. Harruff-Miller, Michael A. Gord, Joseph R. Gord, Elena A. Guliants, Christopher E. Bunker

Electrical and Computer Engineering Faculty Publications

Helium dropletbeam methods have emerged as a versatile technique that can be used to assemble a wide variety of atomic and molecular clusters. We have developed a method to measure the binding energies of clusters assembled in helium droplets by determining the minimum droplet sizes required to assemble and detect selected clusters in the spectrum of the dopeddropletbeam. The differences in the droplet sizes required between the various multimers are then used to estimate the incremental binding energies. We have applied this method to measure the binding energies of cyclic waterclusters from the dimer to the tetramer. We obtain measured …

Time Dynamics Of Self-Pumped Reflection Gratings In A Photorefractive Polymer, Partha P. Banerjee, S. H. Buller, C. M. Liebig, S. A. Basun, Gary Cook, Dean R. Evans, Pierre-Alexandre Blanche, J. Thomas, Cory W. Christenson, N. Peyghambarian

Electrical and Computer Engineering Faculty Publications

The time dynamics of self-pumped reflection gratings in a commonly used photorefractive polymer PDCST:PVK:ECZ-BBP:C60 with no additional electron sources or traps is investigated. While holes are normally the mobile charges and responsible for grating formation, our experimental observations, analyzed using multi-exponential fitting curves, show evidence of electrons in addition to holes as charge carriers, particularly above an applied field of 40 V/μm.

The dependence of effective carrier mobilities on the applied electric field, deduced from experimental results, show stronger field dependence of electron mobility at high electric fields. At an applied field of 70 V/μm, electron and hole mobilities become …

Examination Of The Nonlinear Dynamics Of A Chaotic Acousto-Optic Bragg Modulator With Feedback Under Signal Encryption And Decryption, Mohammed A. Al-Saedi, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

An acousto-optic Bragg cell with first-order feedback, which exhibits chaotic behavior past the threshold for bistability, was recently examined for possible chaotic encryption and recovery of simple messages (such as low-amplitude periodic signals) applied via the bias input of the sound cell driver. We carry out a thorough examination of the nonlinear dynamics of the Bragg cell under intensity feedback for (i) dc variations of the feedback gain (β˜) and the phase shift parameter (α^ 0) and (ii) ac variations of α^ 0; total under signal encryption, investigating both from two different perspectives: (i) examining chaos in view of the …

Commentary And Interpretations Of Tagore’S 'Ode To Africa', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

This is a commentary/interpretation of Rabindranath Tagore's poem "Ode to Africa."

A Novel Qos-Aware Mpeg-4 Video Delivery Algorithm Over The Lossy Ieee 802.11 Wlans To Improve The Video Quality, Tanmoy Debnath

Doctoral

Video traffic is bursty in nature and has different network requirements compared to other types of traffic (e.g. voice, data) in terms of bandwidth, delay, jitter, and loss etc. So it becomes important to manage video traffic on a WLAN carefully to achieve acceptable levels of Quality of Service (QoS). The unique contribution of this work is that it presents experimental and simulation studies of the performance of real video content streamed over WLAN networks. Under various test scenarios the performance of the WLAN network in terms of delay, loss, throughput etc. is analysed in the presence of background traffic. …