Engineering Commons^™

Origami Antennas For Novel Reconfigurable Communication Systems, Xueli Liu

FIU Electronic Theses and Dissertations

Antennas play a crucial role in communication systems since they are the transmitting/receiving elements that transition information from guided transmission to open-space propagation. Antennas are used in many different applications such as aerospace communications, mobile phones, TVs and radios. Since the dimensions of antennas are usually physically proportional to the wavelength at their operating frequencies, it is important to develop large antennas and arrays that can be stowed compactly and easily deployed. Also, it is important to minimize the number of antennas on a platform by developing multifunctional antennas.

The first aim of this research is to develop new deployable, …

Novel Strongly Coupled Magnetic Resonant Systems, Daerhan Liu

FIU Electronic Theses and Dissertations

Wireless power transfer (WPT) technologies have become important for our everyday life. The most commonly used near-field WPT method is inductive coupling, which suffers from low efficiency and small range. The Strongly Coupled Magnetic Resonance (SCMR) method was developed recently, and it can be used to wirelessly transfer power with higher efficiency over a longer distance than the inductive coupling method.

This dissertation develops new SCMR systems that have better performance compared to standard SCMR systems. Specifically, two new 3-D SCMR systems are designed to improve the angular misalignment sensitivity of WPT systems. Their power transfer efficiency for different angular …

Plasmonic Nanoplatforms For Biochemical Sensing And Medical Applications, Arash Ahmadivand

FIU Electronic Theses and Dissertations

Plasmonics, the science of the excitation of surface plasmon polaritons (SPP) at the metal-dielectric interface under intense beam radiation, has been studied for its immense potential for developing numerous nanophotonic devices, optical circuits and lab-on-a-chip devices. The key feature, which makes the plasmonic structures promising is the ability to support strong resonances with different behaviors and tunable localized hotspots, excitable in a wide spectral range. Therefore, the fundamental understanding of light-matter interactions at subwavelength nanostructures and use of this understanding to tailor plasmonic nanostructures with the ability to sustain high-quality tunable resonant modes are essential toward the realization of highly …

Bidirectional Electric Vehicles Service Integration In Smart Power Grid With Renewable Energy Resources, Ahmed A S Mohamed Mr

FIU Electronic Theses and Dissertations

As electric vehicles (EVs) become more popular, the utility companies are forced to increase power generations in the grid. However, these EVs are capable of providing power to the grid to deliver different grid ancillary services in a concept known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V), in which the EV can serve as a load or source at the same time. These services can provide more benefits when they are integrated with Photovoltaic (PV) generation. The proper modeling, design and control for the power conversion systems that provide the optimum integration among the EVs, PV generations and grid are investigated …

Origami Reconfigurable Electromagnetic Systems, Shun Yao

FIU Electronic Theses and Dissertations

With the ever-increasing demand for wireless communications, there is a great need for efficient designs of electromagnetic systems. Reconfigurable electromagnetic systems are very useful because such designs can provide multi-functionality and support different services. The geometrical topology of an electromagnetic element is very important as it determines the element’s RF performance characteristics. Origami geometries have significant advantages for launch-and-carry electromagnetic devices where devices need to fold in order to miniaturize their size during launch and unfold in order to operate after the platform has reached orbit.

This dissertation demonstrates a practical process for designing reconfigurable electromagnetic devices using origami structures. …

Technobiology Paradigm In Nanomedicine: Treating Cancer With Magnetoelectric Nanoparticles, Emmanuel Stimphil

FIU Electronic Theses and Dissertations

Today, cancer is the world’s deadliest disease. Despite significant progress to find a cure, especially over the last decade, with immunotherapy rapidly becoming the state of the art, major open questions remain. Each successful therapy is not only limited to a few cancers but also has relatively low specificity to target cancer cells; although cancer cells can indeed be eradicated, many normal cells are sacrificed as collateral damage. To fill this gap, we have developed a class of multiferroic nanostructures known as magnetoelectric nanoparticles (MENs) that can be used to enable externally controlled high-specificity targeted delivery and release of therapeutic …

Resilient And Real-Time Control For The Optimum Management Of Hybrid Energy Storage Systems With Distributed Dynamic Demands, Christopher R. Lashway

FIU Electronic Theses and Dissertations

A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides …

Electronic And Magnetic Properties Of Two-Dimensional Nanomaterials Beyond Graphene And Their Gas Sensing Applications: Silicene, Germanene, And Boron Carbide, Sadegh Mehdi Aghaei

FIU Electronic Theses and Dissertations

The popularity of graphene owing to its unique properties has triggered huge interest in other two-dimensional (2D) nanomaterials. Among them, silicene shows considerable promise for electronic devices due to the expected compatibility with silicon electronics. However, the high-end potential application of silicene in electronic devices is limited owing to the lack of an energy band gap. Hence, the principal objective of this research is to tune the electronic and magnetic properties of silicene related nanomaterials through first-principles models.

I first explored the impact of edge functionalization and doping on the stabilities, electronic, and magnetic properties of silicene nanoribbons (SiNRs) and …

Tunable, Room Temperature Thz Emitters Based On Nonlinear Photonics, Raju Sinha

FIU Electronic Theses and Dissertations

The Terahertz (10¹² Hz) region of the electromagnetic spectrum covers the frequency range from roughly 300 GHz to 10 THz, which is in between the microwave and infrared regimes. The increasing interest in the development of ultra-compact, tunable room temperature Terahertz (THz) emitters with wide-range tunability has stimulated in-depth studies of different mechanisms of THz generation in the past decade due to its various potential applications such as biomedical diagnosis, security screening, chemical identification, life sciences and very high speed wireless communication. Despite the tremendous research and development efforts, all the available state-of-the-art THz emitters suffer from either being …

Optimum Distribution System Architectures For Efficient Operation Of Hybrid Ac/Dc Power Systems Involving Energy Storage And Pulsed Loads, Ahmed T. Elsayed

FIU Electronic Theses and Dissertations

After more than a century of the ultimate dominance of AC in distribution systems, DC distribution is being re-considered. However, the advantages of AC systems cannot be omitted. This is mainly due to the cheap and efficient means of generation provided by the synchronous AC machines and voltage stepping up/down allowed by the AC transformers. As an intermediate solution, hybrid AC/DC distribution systems or microgrids are proposed. This hybridization of distribution systems, incorporation of heterogeneous mix of energy sources, and introducing Pulsed Power Loads (PPL) together add more complications and challenges to the design problem of distribution systems. In this …

Optimal And Miniaturized Strongly Coupled Magnetic Resonant Systems, Hao Hu

FIU Electronic Theses and Dissertations

Wireless power transfer (WPT) technologies for communication and recharging devices have recently attracted significant research attention. Conventional WPT systems based either on far-field or near-field coupling cannot provide simultaneously high efficiency and long transfer range. The Strongly Coupled Magnetic Resonance (SCMR) method was introduced recently, and it offers the possibility of transferring power with high efficiency over longer distances. Previous SCMR research has only focused on how to improve its efficiency and range through different methods. However, the study of optimal and miniaturized designs has been limited. In addition, no multiband and broadband SCMR WPT systems have been developed and …

Improving Current-Asymmetry Of Metal-Insulator-Metal Tunnel Junctions, Aparajita Singh

FIU Electronic Theses and Dissertations

In this research, Ni–NiOx–Cr and Ni–NiOx–ZnO–Cr metal-insulator-metal (MIM) junction based tunnel diodes have been investigated for the purpose of a wide-band detector. An MIM diode has a multitude of applications such as harmonic mixers, rectifiers, millimeter wave and infrared detectors. Femtosecond-fast electron transport in MIM tunnel diodes also makes them attractive for energy-harvesting devices. These applications require the tunnel diodes to have high current-asymmetry and non-linear current-voltage behavior at low applied voltages and high frequencies. Asymmetric and non-linear characteristics of Ni–NiOx-Cr MIM tunnel diodes were enhanced in this research by the addition of ZnO as a second insulator layer in …

Nanofabrication And Spectroscopy Of Magnetic Nanostructures Using A Focused Ion Beam, Ali Hadjikhani

FIU Electronic Theses and Dissertations

This research used a focused ion beam in order to fabricate record small nano-magnetic structures, investigate the properties of magnetic materials in the rarely studied range of nanometer size, and exploit their extraordinary characteristics in medicine and nano-electronics. This study consists of two parts: (i) Fabrication and study of record small magnetic tunnel junctions (ii) Introduction of a novel method for detection of magnetoelectric nanoparticles (MENs) in the tissue.

A key challenge in further scaling of CMOS devices is being able to perform non-volatile logic with near zero power consumption. Sub-10-nm nanomagnetic spin transfer torque (STT) magnetic tunneling junctions (MTJs) …

Sonochemical Synthesis Of Zinc Oxide Nanostructures For Sensing And Energy Harvesting, Phani Kiran Vabbina

FIU Electronic Theses and Dissertations

Semiconductor nanostructures have attracted considerable research interest due to their unique physical and chemical properties at nanoscale which open new frontiers for applications in electronics and sensing. Zinc oxide nanostructures with a wide range of applications, especially in optoelectronic devices and bio sensing, have been the focus of research over the past few decades. However ZnO nanostructures have failed to penetrate the market as they were expected to, a few years ago. The two main reasons widely recognized as bottleneck for ZnO nanostructures are (1) Synthesis technique which is fast, economical, and environmentally benign which would allow the growth on …

Advanced Graphene Microelectronic Devices, Chowdhury G. Al-Amin

FIU Electronic Theses and Dissertations

The outstanding electrical and material properties of Graphene have made it a promising material for several fields of analog applications, though its zero bandgap precludes its application in digital and logic devices. With its remarkably high electron mobility at room temperature, Graphene also has strong potential for terahertz (THz) plasmonic devices. However there still are challenges to be solved to realize Graphene’s full potential for practical applications.

In this dissertation, we investigate solutions for some of these challenges. First, to reduce the access resistances which significantly reduces the radio frequency (RF) performance of Graphene field effect transistors (GFETs), a novel …

An Optical Design Configuration For Wireless Data Transmission, Seyed Mohammad Amin Motahari Bidgoli

FIU Electronic Theses and Dissertations

The concept of 2D barcodes is of great relevance for use in wireless data transmission between handheld electronic devices. In a typical setup, any file on a cell phone for example can be transferred to a second cell phone through a series of images on the LCD which are then captured and decoded through the camera of the second cell phone. In this research, a new approach for data modulation in 2D barcodes is introduced, and its performance is evaluated in comparison to other standard methods of barcode modulation. In the proposed method, Orthogonal Frequency Division Multiplexing (OFDM) modulation is …

Hybrid Energy Storage Implementation In Dc And Ac Power System For Efficiency, Power Quality And Reliability Improvements, Mustafa Farhadi

FIU Electronic Theses and Dissertations

Battery storage devices have been widely utilized for different applications. However, for high power applications, battery storage systems come with several challenges, such as the thermal issue, low power density, low life span and high cost. Compared with batteries, supercapacitors have a lower energy density but their power density is very high, and they offer higher cyclic life and efficiency even during fast charge and discharge processes. In this dissertation, new techniques for the control and energy management of the hybrid battery-supercapacitor storage system are developed to improve the performance of the system in terms of efficiency, power quality and …

Hybrid Power System Intelligent Operation And Protection Involving Plug-In Electric Vehicles, Tan Ma

FIU Electronic Theses and Dissertations

Two key solutions to reduce the greenhouse gas emissions and increase the overall energy efficiency are to maximize the utilization of renewable energy resources (RERs) to generate energy for load consumption and to shift to low or zero emission plug-in electric vehicles (PEVs) for transportation. The present U.S. aging and overburdened power grid infrastructure is under a tremendous pressure to handle the issues involved in penetration of RERS and PEVs. The future power grid should be designed with for the effective utilization of distributed RERs and distributed generations to intelligently respond to varying customer demand including PEVs with high level …

Development Of Hardware In The Loop Real-Time Control Techniques For Hybrid Power Systems Involving Distributed Demands And Sustainable Energy Sources, Ali Mazloomzadeh

FIU Electronic Theses and Dissertations

The future power grid will effectively utilize renewable energy resources and distributed generation to respond to energy demand while incorporating information technology and communication infrastructure for their optimum operation. This dissertation contributes to the development of real-time techniques, for wide-area monitoring and secure real-time control and operation of hybrid power systems.

To handle the increased level of real-time data exchange, this dissertation develops a supervisory control and data acquisition (SCADA) system that is equipped with a state estimation scheme from the real-time data. This system is verified on a specially developed laboratory-based test bed facility, as a hardware and software …

Wireless Sensor Network Deployment, Yipeng Qu

FIU Electronic Theses and Dissertations

Wireless Sensor Networks (WSNs) are widely used for various civilian and military applications, and thus have attracted significant interest in recent years. This work investigates the important problem of optimal deployment of WSNs in terms of coverage and energy consumption. Five deployment algorithms are developed for maximal sensing range and minimal energy consumption in order to provide optimal sensing coverage and maximum lifetime. Also, all developed algorithms include self-healing capabilities in order to restore the operation of WSNs after a number of nodes have become inoperative.

Two centralized optimization algorithms are developed, one based on Genetic Algorithms (GAs) and one …

Structural Health Monitoring Inside Concrete And Grout Using The Wireless Identification And Sensing Platform (Wisp), Elicek Delgado Cepero

FIU Electronic Theses and Dissertations

This research investigates the implementation of battery-less RFID sensing platforms inside lossy media, such as, concrete and grout. Both concrete and novel grouts can be used for nuclear plant decommissioning as part of the U.S. Department of Energy’s (DOE’s) cleanup projects. Our research examines the following: (1) material characterization, (2) analytical modeling of transmission and propagation losses inside lossy media, (3) maximum operational range of RFID wireless sensors embedded inside concrete and grout, and (4) best positioning of antennas for achieving longer communication range between RFID antennas and wireless sensors. Our research uses the battery-less Wireless Identification and Sensing Platform …

System-On-A-Chip (Soc) Based Hardware Acceleration In Register Transfer Level (Rtl) Design, Xinwei Niu

FIU Electronic Theses and Dissertations

Today, modern System-on-a-Chip (SoC) systems have grown rapidly due to the increased processing power, while maintaining the size of the hardware circuit. The number of transistors on a chip continues to increase, but current SoC designs may not be able to exploit the potential performance, especially with energy consumption and chip area becoming two major concerns. Traditional SoC designs usually separate software and hardware. Thus, the process of improving the system performance is a complicated task for both software and hardware designers. The aim of this research is to develop hardware acceleration workflow for software applications. Thus, system performance can …

A Highly Efficient Biometrics Approach For Unconstrained Iris Segmentation And Recognition, Yu Chen

FIU Electronic Theses and Dissertations

This dissertation develops an innovative approach towards less-constrained iris biometrics. Two major contributions are made in this research endeavor: (1) Designed an award-winning segmentation algorithm in the less-constrained environment where image acquisition is made of subjects on the move and taken under visible lighting conditions, and (2) Developed a pioneering iris biometrics method coupling segmentation and recognition of the iris based on video of moving persons under different acquisitions scenarios. The first part of the dissertation introduces a robust and fast segmentation approach using still images contained in the UBIRIS (version 2) noisy iris database. The results show accuracy estimated …

Secure Routing And Trust Computation In Multihop Infrastructureless Networks, Tirthankar Ghosh

FIU Electronic Theses and Dissertations

Today's wireless networks rely mostly on infrastructural support for their operation. With the concept of ubiquitous computing growing more popular, research on infrastructureless networks have been rapidly growing. However, such types of networks face serious security challenges when deployed. This dissertation focuses on designing a secure routing solution and trust modeling for these infrastructureless networks.

The dissertation presents a trusted routing protocol that is capable of finding a secure end-to-end route in the presence of malicious nodes acting either independently or in collusion, The solution protects the network from active internal attacks, known to be the most severe types of …

Modified Diamond Dipole Antenna For Ultra Wideband Communications Using Finite Difference Time Domain Method, Srinivas Desamsetty

FIU Electronic Theses and Dissertations

The aim of this thesis is to analyze and design ultra wideband antennas for personal communication devices using Finite Difference Time Domain (FDTD) method. Initially diamond dipole, an ultra wideband antenna is selected from the literature and analyzed. The shape of the diamond dipole is modified in such a way that the straight-line base of the two triangular arms (near the feed) is replaced with an arc. The resulting antenna is named as modified diamond dipole. Performance is observed by varying radius of curvature of base of triangular arms (for constant flare angle) and by varying flare angle (for constant …

Predictive Performance Modeling And Simulation, Garth Crosby

FIU Electronic Theses and Dissertations

The purpose of this thesis was to create and simulate a model of an existing Campus network with a view to predict future performance. This thesis also suggests ways in which such a network can be optimized.

Such simulation and modeling can be referred to as "Predictive Performance Modeling'. In this research a model of Florida International University (University Park campus) High Speed Network was created. Simulation of the model was carried out and an ATM Backbone Analysis was done. The results obtained were compared with corresponding results obtained by network performance monitoring and measurement software tools. A strong correlation …

Yttria Stabilized Zirconia Buffered Silicon: Substrates For Ybco Microwave Applications, Philip D. Brown

FIU Electronic Theses and Dissertations

The use Yttria-Stabilized Zirconia (YSZ) as a buffer layer for YBa₂Cu₃O_7-x (YBCO) thin films on (100) silicon (Si) substrates is investigated. YSZ was grown using on-axis pulsed D.C. (PDC) and R.F. magnetron sputtering from a 99.9% pure YSZ target [(Y₂O₃)_0.08(ZrO₂)_0.92]. Sputtering was carried out in Argon/Oxygen atmosphere at total pressures ranging from 6 to 320 mTorr containing 0.1 to 10% Oxygen. Substrate temperatures were varied from 300° C to 900° C. (111), (100) and mixed (100) and (111) oriented YSZ films were produced …

Intelligent Dynamic Space Management Systems, Margaret-Rose Madeleine Dabdoub

FIU Electronic Theses and Dissertations

The objective of this work is to design, simulate and synthesize a dynamic space controller system. The concept of space allocation and management can be applied to more than physical space. It may also be taken in the contexts of memory, network or bus management. The management and allocation of any space depends mostly on the twin factors of demand and availability. Time, the size and amount of space available, as well as the number of requests for the spaces, must also be considered. The proposed design has the capability to monitor multiple spaces for vacancies, length of time occupied …