Electromagnetic Wave Theory and Applications

Contains reports on eleven research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)Joint Services Electronics Program (Contract DAAL03-86-K-0002)National Science Foundation (Grant ECS82-03390)National Science Foundation (Grant ECS85-04381)Schlumberger-Doll Research CenterNational Aeronautics and Space Administration (Contract NAG 5-141)National Aeronautics and Space Administration (Contract NAS 5-26861)National Aeronautics and Space Administration (Contract NAG 5-270)U.S. Navy - Office of Naval Research (Contract N00014-83-K-0258)National Aeronautics and Space Administration (Contract NAG 5-725)International Business Machines, Inc.Lincoln Laborator

Modeling and design of superconducting microwave passive devices and interconnects

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (p. 157-163).by Laurence H. Lee.Ph.D

Optical properties of polymers and their applications

The last decade has witnessed explosive growth in the world of photoactive polymers for a variety of applications in several sectors of the global economy. The need for efficient, reliable, and low-cost data acquisition, storage, processing, transmission, and display technologies has made it necessary for research aimed at addressing these needs. Recent accomplishments in this materials area represent exciting opportunities for major innovations in various fields. However, further work needs to be done to transfer the technology from fundamental R&D to manufacturing. The goal of this study is to provide a better understanding of the optical properties of polymers and identify the candidates that are ideal for a variety of applications. The fundamental optical properties and characteristics of several commonly used polymers are presented in this study. Mathematical simulations of signal propagation through a polymer core waveguide are examined to determine the materials that are most suitable for long range communications. Other applications such as electronic devices, temperature and pressure sensors, protective coatings and energetic materials are briefly considered. Self-healing and self-repair in polymers are examined

Measuring the Photon Energy Scale through Test Beam Data

This dissertation aims at measuring the photon energy scale combining specialized Monte Carlo simulation with data taken during the combined ATLAS test beam in 2004. This work explains the steps taken to arrive at the photon energy scale, starting from the knowl- edge acquired for electrons. The chapters are structured as follows: Chapters 1 and 2 briefly introduce this work and the motivation behind it. Chapter 3 gives an overview of the LHC ex- periment and the ATLAS detector as a whole. Chapters 4 and 5 address in detail the ATLAS electromagnetic calorimeter and signal reconstruction at the cell level. Chapter 6 concentrates on the setup for the combined test beam with emphasis on the photon run. Chapter 7 details the event selection strategy used for the photon run analysis. Chapter 8 describes the generation and tuning of the special Monte Carlo for the photon run. Chapter 9 focuses on the highly special- ized Monte Carlo studies that employed special calibration objects known as calibration hits. Chapter 10 details the methodology behind the measurement of the photon scale and evaluates it in terms of the electromagnetic calorimeter resolution. Chapters 11 and 12 present a summary of the results and the conclusions, respectively

Nanoelectronics in Oxides and Semiconductors

The success of silicon industry lies on three major properties of silicon, an easily formed oxide layer to allow field effect operation, tunability of carrier density and high device scalability. All these features exist in oxides, together with some novel properties such as ferroelectricity, magnetic effects and metal-insulator transition. With the recent development in material growth method including molecular beam epitaxy (MBE), pulsed laser deposition (PLD) and reflection high energy electron diffraction (REED), atomically engineered oxide interfaces become available, thus opening the door to the novel oxide nanoelectronics. In this dissertation we create and study nanoelectronics in oxides, semiconductors and hybrid of these two. We used a conductive atomic force microscope tip to write single electron transistors in the 3-unit-cell-LaAlO3/SrTiO3 heterostructure and observed ferroelectric tunneling behaviors. We also fabricated ferroelectric field transistors directly on silicon using strained SrTiO3 ferroelectric film and further confirmed the ferroelectric properties of this device. Meanwhile, we developed an ultrasensitive microwave capacitance sensor to study the electronic properties of self-assembled quantum dots and the switching mechanism of memristive devices. The integration of this sensor to a home made atomic force microscope provides an important tool to study the dielectric properties at nanoscale

Terahertz response of microfluidic-jetted fabricated 3D flexible metamaterials

Conventional materials exhibit some restrictions on their electromagnetic properties. Especially in terahertz region, for example, materials that exhibit magnetic response are far less common in nature than materials that exhibit electric response. However, materials can be designed, namely artificial man-made metamaterials that exhibit electromagnetic properties that are not found in natural materials by adjusting, for example, the dielectric, magnetic or structural parameters of the constituent elements. This dissertation demonstrates the use of new fabrication techniques to construct metamaterials in THz range via a material deposition system. The metamaterials are fabricated by stacking alternative layers with conventional designs such as single ring- split ring resonators (SRR) and microstrips to form a 3D metamaterial structure. Conductive nano-particle Ag, Cu and semiconductor polymer fluids are used as structural mediums. The metamaterials are fabricated on polyimide substrate. Their flexible nature will be advantageous in future device innovations. In order to obtain electromagnetic resonance in the terahertz range, the dimensions of the single ring-SRR and microstrips are first approximated by analytical methods and then confirmed by numerical simulation. The fabricated metamaterials are then characterized in transmission mode using Time-domain THz Spectroscopy (THz-TDS) in the 0.1 to 2 THz range

Electrochemical method for the determination of arsenic 'in the field' using screen-printed grid electrodes

This project describes development and problem solving efforts to realise a viable portable sensor for arsenic, applicable to drinking water. The work is the first dedicated effort towards this goal, after the preliminary investigations previously conducted at Cranfield University (Cooper, 2004 and Noh, 2005). Using polymeric gold ink BQ331 (DuPont Microcircuit Materials, Bristol, UK) as working electrode on screen printed strips, the electrochemical procedure was studied. Due to the wealth of research on electrochemical and non electrochemical methods for arsenic determination, this project attempts to capitalise on the unique advantages of the screen-printed gold surface. In particular, the issues surrounding the performance of the sensor were evaluated by electrochemical and spectroscopic means (including infrared, nuclear magnetic resonance and X-ray photoelectron spectroscopy). A number of custom screen printed electrodes were prepared in house comparing sensor performance on compositional factors. An interference coming from silver interaction with chloride in the reference electrode was identified. As such, the design of the sensor needs to change to include either an immobilising layer, such as Nafion, over the silver, or to omit screen-printed silver altogether. The Nafion was presumed to work by excluding (or at least much reducing) the passage of negatively charged chloride ions to the silver surface preventing formation of soluble silver chloride complexes. The design of the sensor was considered in light of performance and sensitivity. The screen-printed electrodes were cut to facilitate a microband design lending favourable diffusive to capacitive current characteristics. With this design, As(III) detection was demonstrated comfortably at 5 ppb (in a copper tolerant 4 M HCl electrolyte) without electrode need for additional preparation procedures. This is below the World Health Organisation (WHO) guideline and United States Environmental Protection Agency (USEPA) regulation level of 10 ppb in drinking water. The electrode materials are already mass manufacturable at an estimated cost less than £ 0.5 per electrode. Themicroband design could, in principle, be applied to mercury and other metal ions. The procedure for As(V) either with chemical or electrochemical reduction and determination still needs to be assessed. However, the presented electrode system offers a viable alternative to the colorimetric test kits presently employed around the world for arsenic in drinking water. Also, the Nicholson Method (Nicholson, 1965a), used for characterising electron transfer kinetics at electrode surfaces, was extended for application to rough surfaces using a fractal parameter introduced by Nyikos and Pajkossy (1988). This work includes mathematical derivation and numerical evaluation and gives a number of predictions for electrochemical behaviour. These predictions could not be tested experimentally, as yet, since the physical conditions must be carefully controlled

Graphene-SiC particle reinforced aluminum alloy composite foam : response to high strain rate deformation

Aluminum foams are becoming potential material for multifunctional applications because it is lightweight and has excellent combination of physical and mechanical properties and noise and vibration mitigation characteristic. Because of its cellular structure, it exhibits excellent damping capacity, sound and noise absorption, shock and impact energy absorption. Applications of metal foam for energy absorption and crashworthiness require knowledge on their compressive deformation response at various strain rates. The properties of metal foam are dependent on cell wall mechanical properties and their microstructure. Cell wall properties have been improved by adding Graphene Nano platelets as reinforcement to the Al-foam. This investigation is related to the study of quasi-static compressive behavior and the high strain rate response under dynamic compressive loading in Graphene Al foam. The experimental results show that the peak, plateau stress and energy absorption of reinforced foam is much higher than unreinforced foam. The high strain rate compressive behavior of Graphene Al foam been studied using the split Hopkinson pressure bar apparatus. It is found that peak stress, plateau stress and energy absorption of Graphene Al foam increases as the strain rate increases over a range of strain rate from 500 s-1 to 2760 s-1. Thus, the Graphene Al foam is strain rate sensitive the plateau stress and energy absorption in the Graphene -Al foam increased by about two times and three times, respectively, compared to unreinforced foam

The application of laser-generated ultrasound to the study of aluminium-epoxy bonded systems

The poor performance of acoustic wave techniques in predicting adhesively-bonded joint failure under destructive loading is a long-standing problem, known to derive from unreliable adhesive defect detection. This thesis examines the feasibility of applying a relatively new technique, generating ultrasound with pulsed Nd:YAG lasers, to the study of aluminium alloy adherends joined by epoxy layer bonds. Laser generation is a non-contacting method which produces highly repeatable ultrasonic sources in metals, without damping motion at the sample surface. Pulses created in this fashion have bandwidths around 20 MHz and radiate both along the sample surface and into the material bulk. Displacements at the sample surface recorded by a broad bandwidth non-contact detector, such as a 532 nm wavelength laser Michelson interferometer, are therefore able to resolve details in time-varying traces which are not visible when narrowband transducers are used. In particular, individual reverberations between the interfaces of epoxy layers less than 100 μm thick are detected in transmission through adhesively bonded joints, on time domain traces. An epoxy layer sandwiched between two thick aluminium adherends presents a three layer case which is seldom discussed in the literature. I have therefore adapted theory developed for surface waves in thin layers overlying deep substrates, and for waves transmitted through multilayer structures, into an explicit formulation for an elastic layer embedded in adherend half-spaces that can be used for both through-transmission and interface-parallel waves. The case of travelling waves in a viscoelastic layer has not yet been examined as the current formulation requires unfeasibly long computation times. A numerical solution assuming elastic behaviour, gives strong indications that embedded epoxy layers support travelling waves directed along the interfaces, despite the fact that a single interface between epoxy and aluminium will not support non-dispersive Stoneley interface waves. Experimental work presented in Chapters 4 to 7 is preceded by a review of laser generation and non-contact detection methods, which introduces techniques that I have employed. As well as using laser interferometers, 1 have also built my own electromagnetic acoustic transducers (EMATs), to provide a cheaper alternative detection scheme. Chapter 4 concentrates upon on-epicentre detection of direct through transmission pulse arrivals, using analysis both of the entire reverberation wavetrain following the main arrival and of consecutive pulses within it, in order to extract information on the bonds' cohesive and adhesive properties. Chapter Five examines variations in surface-travelling waveforms on unbonded, free-surface aluminium plates with thicknesses varying from 63 mm down 28 μm, in a search for non- dispersive waves that would be suitable for probing adhesive bonds. Rayleigh arrivals on samples over 10 mm thick and the symmetric zero-order Lamb mode on plates under 200 μm thick both propagate from the NdtYAG laser source as sharp pulses, but intermediate plate thicknesses only allow waves with highly dispersive characteristics, which tend to mask any dispersion due to bonds. The plate wave experiments allow a full intercomparison between interferometer and EMATs, both out-of-plane motion sensitive and in-plane motion sensitive. Chapter 6 uses Rayleigh-like surface waves travelling along 25 mm thick adherends to initiate interface-parallel travelling waves in an adhesive layer bonding a second adherend to the surface, which are subsequently detected on emerging at the free surface beyond the bond. These surface-interface-surface travelling (SIST) waves penetrate under increasingly longer bonds as the wave frequency decreases, a fact confirmed by the behaviour of pulses given a narrowband frequency modulation when generating laser beams interfere to produce a spatially modulated source. The interference source optical arrangement, described in Chapter 5, can be altered to give Rayleigh arrival modulation frequencies from 20 MHz to below 1 MHz. Finally, Chapter 7 examines alternative pathways for surface waves incident upon the edge of a bonded joint region, and demonstrates that SIST waves are an efficient mechanism for transferring ultrasound between the two adhesive-adherend interfaces, given the observed emergence of clearly discernible SIST waves on the second adherend of a lapped bond joint. I conclude that through transmission pulse analyses arc capable of extracting quantitative information about bond properties and should be developed as the basis for laser generated ultrasonic bond testing. SIST waves, however, require further research before they can be employed in a practical manner