Electrical and Computer Engineering Commons^™

Compact Concentric Annular-Ring Patch Antenna For Triple Frequency Operation, Xiulong Bao, Max Ammann

Articles

A novel single-layer, single-feed concentric annular-ring microstrip patch antenna providing triple-frequency operation is proposed and experimentally studied. This is achieved by embedding a small circular patch into a dual stub-loaded concentric annular-ring structure and by employing a cross-slot in the ground plane. The proposed technique can provide triple-band operation and reduce the antenna size by over 50% compared to the conventional annular-ring patch antenna for a given frequency. Experimental results show the proposed antenna to have impedance bandwidths of 6.38, 6.30 and 35% for the three bands, at 1.17, 1.428 and 1.9 GHz, respectively. The proposed structure is capable of …

From L-Shaped Planar Monopoles To A Novel Folded Antenna With Wide Bandwidth, Giuseppe Ruvio, Max Ammann

Articles

A novel folded monopole antenna is investigated numerically and experimentally. The proposed antenna comprises a short folded monopole suitably shaped at the base with two vertical grounding probes. This small antenna is shown to have a fractional impedance bandwidth up to 125% (1.6 GHz to 7.5 GHz) for a 10 dB return loss. An interesting compromise between impedance bandwidth and pattern control is found by tuning a double side bevel at the base of the monopole, the position of the feeding point and its distance from the ground plane. Measurements and simulations are in good agreement and show a dramatic …

All-Fiber Multimode-Interference-Based-Refractometer Sensor:Proposal And Design, Qian Wang, Gerald Farrell

Articles

A novel all-fiber refractometer sensor is proposed, which is based on multimode interference in the multimode fiber core section sandwiched between two single-mode fibers. A wide-angle beam propagation method in the cylindrical coordinate is employed as the modeling tool for simulation and design of the proposed refractometer sensor. The design for a refractometer is presented that shows that the refractometer would have an estimated resolution of 5.4×10−5 for refractive indices from 1.33 to 1.45 and of 3.3×10−5 for refractive indices from 1.38 to 1.45 through the choice of an appropriate length of the multimode fiber core section.

Analysis Of Strain And Intermixing In Single-Layer Ge/Si Quantum Dots Using Polarized Raman Spectroscopy, Anna Baranov, A. V. Federov, Tatiana Perova, R. A. Moore, V. Yam, D. Bouchier, V. Le Thanh, Kevin Berwick

Articles

The built-in strain and composition of as-grown and Si-capped single layers of Ge∕Si dots grown at various temperatures (460–800 °C) are studied by a comparative analysis of the Ge-Ge and Si-Ge modes in the polarized Raman spectra of the dots. A pronounced reduction of the strain and Ge content in the dots after deposition of the cap layer at low temperatures is observed, indicating that strain-induced Si diffusion from the cap layer is occurring. For large dots grown at 700–800 °C the observations are in agreement with a model of the Ge∕Si dot consisting of a Si-rich boundary region and …

Design Of One-Dimensional Composite Photonic Crystals With An Extended Photonic Band Gap, Vladimir Tolmachev, Kevin Berwick

Articles

A technique for photonic band gap (PBG) extension based on mixing photonic crystals with different lattice constants or filling factors is suggested. For the design of photonic crystals with maximal PBG extension the gap map imposition method is utilized. Gap maps for composite photonic crystals based on Si-air structures are calculated and used to predict optimal structures for fabrication.

The Human Eye Position Control System In A Rehabilitation Setting, Yvonne Nolan, Ted Burke, C. Boylan, Annraoi De Paor

Articles

Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y) system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for …

Study Of Transmission Response Of Edge Filters Employed In Wavelength Measurements, Qian Wang, Gerald Farrell, Thomas Freir

Articles

The ratiometric wavelength-measurement system is modeled and an optimal design of transmission response of the employed edge filter is demonstrated in the context of a limited signal-to-noise ratio of the signal source. The corresponding experimental investigation is presented. The impact of the limited signal-to-noise ratio of the signal source on determining the optimal transmission response of edge filters for a wavelength-measurement application is shown theoretically and experimentally.

Printed Triband Terminal Antenna, Matthias John, Max Ammann, R. Farrell

Articles

This paper presents a printed triple-band multibranch monopole for use in modern wireless systems. The antenna is designed to operate in three bands which cover virtually all wireless channels. Parameters of the antenna geometry are varied and the effects of these variations on the impedance bandwidth are shown.

Theoretical And Experimental Investigations Of Macro-Bend Losses For Standard Single Mode Fibers, Qian Wang, Gerald Farrell, Thomas Feir

Articles

Modeling of macro-bend losses for single mode fibers with multiple cladding or coating layers is presented. Macro-bend losses for standard single mode fibers (SMF28) are investigated theoretically and experimentally, showing that the inner primary coating layer of SMF28 has a significant impact on the bend losses and most of the radiation field is absorbed in the inner primary coating layer of SMF28. The agreement between theoretical calculations and experimental measurements suggests that the so-called elastooptical correction in modeling is not required for SMF28.

Use Of Advanced Synthesis Tools In Teaching Vlsi Design, Kevin Berwick, Dominic Nardone

Articles

No abstract provided.

The Effect Of The Internal Field On The Ir Absorption Spectra Of Small Particles In Case Of 3d, 2d And 1d Size Confinement, Igor I. Shaganov, Tatiana S. Perova, R. Alan Moore, Kevin Berwick

Articles

The spectral properties of composite materials based on small particles under 1D, 2D, and 3D size confinement are described using a combination of dispersive internal field and effective media theory approaches. Calculations performed for a number of crystalline materials have shown that the peak position and intensity of the vibrational band of the material under conditions of 1D, 2D, and 3D size confinement are changed, whereas the bandwidth of the band remains the same. In the case of 3D confinement, the peak position of the spectrum of isolated “mesoparticles” ( ) appears to be very close to the intrinsic frequency …

Optimum Design Of The Printed Strip Monopole, Max Ammann, Matthias John

Articles

A monopole antenna, printed on low-cost laminate and fed by a microstrip line, is examined. These types of antennas are becoming popular in view of their broad bandwidth and low-profile structure, enabling easy integration as a terminal antenna. The move away from a classical ground plane (with normal radiator) is one of the attractive features of these antennas, but the full effects of the radiator and ground plane being on opposite sides of the same laminate are often not investigated. The effect of these ground planes on the impedance bandwidth and radiation pattern is investigated experimentally and numerically.

Optimization Of Impedance Bandwidth For The Printed Rectangular Monopole Antenna, Matthias John, Max Ammann

Articles

This paper describes a printed rectangular-plate monopole fed by microstrip line. The effect of varying the plate width, feed-gap height, and feedline width on the impedance bandwidth is examined. It is shown that for a fixed ground-plane size, that optimization of these parameters can yield an impedance bandwidth ratio of 4.3:1, without using any broadbanding techniques.

An Explicit Mapping Between The Frequency Domain And The Time Domain Representations Of Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

Explicit expressions are presented that describe the input-output behaviour of a nonlinear system in both the frequency and the time domain. The expressions are based on a set of coefficients that do not depend on the input to the system and are universal for a given system. The anharmonic oscillator is chosen as an example and is discussed for different choices of its physical parameters. It is shown that the typical approach for the determination of the Volterra Series representation is not valid for the important case when the nonlinear system exhibits oscillatory behaviour and the input has a pole …

A New High Power Parallel Converter Scheme For Active Power Filters, Malabika Basu, S. P. Das, Gopal Dubey

Articles

A new topology for efficient utilisation of parallel converters as VAR compensators and active power filters (APF) for high power loads is proposed. Because of limited power handling capacity of individual devices, paralleling is the choice to increase rating of equipment, while keeping the THD of the current at the PCC within the agency specified standards. It has been reported in the literature that paralleling several converters, rather than switches, is more reliable in sharing of load. From this perspective, multilevel converters carry lot of weight, as their typical power circuit configuration limits the stress on individual devices to an …

A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke

Articles

We present a system designed to study the pressure at various ‘hot spots’ on the back of the body and the deformation of the spine experienced by a patient when strapped to a spinal board, and the potential alleviation of both by the addition of an inflatable “spinal raft” (or other similar device). In measuring pressure we devised a system of air-filled sacks interfaced with a PC. Each sack, placed under a particular key point on the body, is inflated until its faces just begin to separate and a switch thereby opens. The pressure reading is then captured and displayed …

A Vocalisation-Based Drawing Interface For Disabled Children, Ted Burke

Articles

In our work with disabled children at Ireland’s National Rehabilitation Hospital, a problem we have experienced in the facilitation of art activities is that traditional art materials and standard computer drawing programs sometimes prove inaccessible. In this paper, an original system, called “PaintMyVoice” is presented which facilitates the creation of two or three-dimensional images using a variety of novel input modalities. In particular, vocalisations can be used to create original images of a variety of objects, including trees, flowers and landscape elements. Additional input to the system can optionally be provided via mouse, keyboard, switch interface or digital camera depending …

Liquid Crystal Based Optical Switches, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell

Articles

Optical switches using two electro-optical effects in liquid crystals are proposed and investigated for incorporation in a switch matrix for optical networks. These two devices employ selective reflection in cholesteric layers and total reflection at the border between glass and nematic liquid crystal. Prototypes of these switches have been designed and their parameters have been investigated. Initial results suggest the switching contrast ratio of 38.5 and 42 dB, respectively, with insertion loss about 2.3…2.9 dB for polarized light.

Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell

Articles

Coupling efficiency between two step- index multimode fibers of different numerical aper- tures with an angular misalignment is calculated. The theory is presented using radiometry and geometrical optics. The limit case of the calculation is consistent with a previously published result. The results may be useful for applications such as power launching between two types of fibers with different numerical apertures for example silica fiber and plastic optical fiber(POF) and with an angular misalignment.

On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

Novel constructions of empirical controllability and observability gramians for nonlinear systems for subsequent use in a balanced truncation style of model reduction are proposed. The new gramians are based on a generalisation of the fundamental solution for a Linear Time-Varying system. Relationships between the given gramians for nonlinear systems and the standard gramians for both Linear Time-Invariant and Linear Time-Varying systems are established as well as relationships to prior constructions proposed for empirical gramians. Application of the new gramians is illustrated through a sample test-system.

Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith

Articles

In this work a number of techniques (electronic speckle pattern interferometry, holographic interferometry, strain gauge and finite element method) are brought to bear in order to establish consistency in the results of strain measurement. This is necessary if optical nondestructive testing methods, such as those used here, are to gain acceptance for routine industrial use. The FE model provides a useful check. Furthermore, ESPI fringe data facilitates the extension of FE models, an approach that is of growing importance in component testing. The use of in-plane and out-of-plane sensitive electronic speckle pattern interferometry (ESPI) for non-destructive material characterization of thick …

Study Of Structure And Quality Of Different Silicon Oxides Using Ftir And Raman Microscopy, C. Moore, T. S. Perova, B. Kennedy, Kevin Berwick, I. I. Shaganov, R. A. Moore

Articles

In this work, SiO₂ and fluorine and phosphorous doped SiO₂ thin films are investigated using FTIR and Raman techniques. FTIR spectroscopy was performed at normal and oblique incidence of the probe beam in transmission and reflection modes. The effect of polarisation and angle of incidence of the probe beam is examined for the case of reflection mode. Infrared spectra taken from doped oxides show that the structure changes with the passage of time. Alternate methods to calculate the thickness of the doped film are therefore discussed. Infrared spectra of electron beam evaporated oxides give valuable information on their …

Circular Annular Planar Monopoles With Em Coupling, Z. N. Chen, Max Ammann, M.Y. W. Chia, T.S. P. See

Articles

A circular annular planar monopole with electromagnetic coupling shows broadband properties. The planar radiator is electromagnetically coupled with a probe-fed strip, and separated from it by a thin dielectric sheet. The parametric effects on the bandwidth are examined experimentally. The measurements demonstrate that the proposed monopoles have the merit of broad impedance bandwidths in the order of 100% for VSWR=2:1 and of 4:1 for VSWR=3:1 and acceptable radiation patterns across the bandwidths.

A Wide-Band Shorted Planar Monopole With Bevel, Max Ammann, Zhi Ning Chen

Articles

A new wide-band shorted planar monopole with a bevel is presented. The numerical simulations and measurements demonstrate that the impedance bandwidth of a wide-band planar square monopole is shown to increase dramatically by combining bevelling and a shorting technique. The radiation pattern stability is also discussed.

Optimization And Comparison Of Broadband Monopoles, Z. N. Chen, M.Y. W. Chia, Max Ammann

Articles

The impedance and radiation properties of four broadband monopoles are compared and the parameters of a new roll monopole are optimised experimentally and numerically. The performances of the roll monopole with various numbers of roll turns are discussed and optimised numerically. The measurements and simulations show that, compared with conventional broadband monopoles, the roll monopole

Optical Switches Using Electro-Optical Effects In Liquid Crystals, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell

Articles

A simple displacement sensor based on a bent singlemode-multimode-singlemode (SMS) fiber structure is proposed and experimentally investigated. The sensor offers a wider displacement range, not limited by the risk of fiber breakage, as well as a three-fold increase in displacement sensitivity by comparison with a straight SMS structure sensor. This sensor can be interrogated by either an optical spectral analyzer (OSA) or a ratiometric interrogation system: (1) if interrogated by an OSA assuming a resolution of 1 pm, it has a sensitivity of 28.2 nm for a displacement measurement range from 0 to 280 μm; (2) if interrogated by a …

Design Criteria And Optical Characteristics Of One-Dimensional Photonic Crystals Based On Periodically Grooved Silicon, Vladimir Tolmachev, Tatiana Perova, Kevin Berwick

Articles

Photonic bandgap (PBG) regions have been calculated for periodically grooved Si structures, acting as a one-dimensional photonic crystal. The wavelength range of the PBG as a function of the ratio (D_Si/A) is presented, where D_Si is the width of the Si walls and A is the grooved silicon lattice constant. The influence of the parameter D_Si, the refractive index of the space between the Si walls and the number of structure periods, m, on the forming of PBG regions is discussed. A good correlation between the calculated and the experimentally observed …

Precise Chemical Analysis Development For Si And Gaas Surfaces, T. A. Briantseva, Z. M. Lebedeva, D. V. Lioubtchenko, M. Nolan, T. S. Perova, R. A. Moore, Kevin Berwick

Articles

Precise chemical analysis (PCA) was developed to allow the study of non-interconnected atoms on crystalline semiconductor surfaces, such as those produced during rapid thermal processing (RTP) of silicon and electron beam lithography on gallium arsenide (GaAs). The PCA method is based on selectively dissolving the different components present on the semiconductor surface using preferential etchant solutions. After etching, the etchant solution, containing the etched component, is analyzed by a photometric technique. In this paper, we present photometric measurements of the amount of “free” (non-interconnected) atoms that remain on semiconductor surfaces following electron beam and RTP processing. In this context, “free” …

Sharing Health-Care Records Over The Internet, Jane Grimson, Gaye Stephens, Benjamin Jung, William Grimson, Damon Berry, Sebastien Pardon

Articles

Presents a novel approach to sharing electronic health-care records that leverages the Internet and the World Wide Web, developed as part of two European Commission-funded projects, Synapses and SynEx. The approach provides an integrated view of patient data from heterogeneous, distributed information systems and presents it to users electronically. Synapses and SynEx illustrate a generic approach in applying Internet technologies for viewing shared records, integrated with existing health computing environments. Prototypes have been validated in a variety of clinical domains and health-care settings

The Problem Of A Viscoelastic Cylinder Rolling On A Rigid Half-Space, John Murrough Golden, G.A.C. Graham

Articles

The problem of a viscoelastic cylinder rolling on a rigid base, propelled by a line force acting at its centre, is solved in the noninertial approximation. The method used is based on a decomposition of hereditary integrals developed by the authors in previous work, and on the viscoelastic Kolosov-Muskhelishvili equations which are used to generate a Hilbert problem. In this formulation, the problem reduces to a nonsingular integral equation in space and time, which simplifies under steady-state conditions and for exponential decay materials, to algebraic form. There are also two subsidiary conditions.

In the case of a standard linear model, …