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Electrical and Computer Engineering

Infrared

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Articles 31 - 43 of 43

Full-Text Articles in Engineering

Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri Jan 2012

Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri

Electronic Theses and Dissertations

Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. • A broadband technique by …

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Infrared Tapered Slot Antennas Coupled To Tunnel Diodes, Louis A. Florence Jan 2012

Infrared Tapered Slot Antennas Coupled To Tunnel Diodes, Louis A. Florence

Electronic Theses and Dissertations

Tapered slot antennas (TSAs) have seen considerable application in the millimeter-wave portion of the spectrum. Desirable characteristics of TSAs include symmetric E- and H-plane antenna patterns, and broad non-resonant bandwidths. We investigate extension of TSA operation toward higher frequencies in the thermal infrared (IR), using a metal-oxide-metal diode as the detector. Several different infrared TSA design forms are fabricated using electronbeam lithography and specially developed thin-film processes. The angular antenna patterns of TSA-coupled diodes are measured at 10.6 micrometer wavelength in both E- and H-planes, and are compared to results of finite-element electromagnetic modeling using Ansoft HFSS. Parameter studies are …

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Formation Of Infrared Windows Of Transparency In One-Dimensional Silicon Photonic Crystals, Anna Baldycheva, Vladmir A; Tolmachev, Tatiana S. Perova, Kevin Berwick Jan 2011

Formation Of Infrared Windows Of Transparency In One-Dimensional Silicon Photonic Crystals, Anna Baldycheva, Vladmir A; Tolmachev, Tatiana S. Perova, Kevin Berwick

Articles

The optical properties of three-component one-dimensional photonic crystal (1-D PC) structures were investigated by modeling them as two-component PCs with an additional regular t-layer, using the gap map approach and the transfer matrix method. Numerical results demonstrate that the introduction of the t-layer affects the properties of the high-order photonic band gaps, replacing them with transmission bands and creating regions of transparency over certain wavelength ranges. For the first time, a map of the transmission bands for a three-component 1-D PC was generated. This map constitutes a unique design tool for infrared optical filters for silicon-based photonic integrated …

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Shift Estimation Algorithm For Dynamic Sensors With Frame-To-Frame Variation In Their Spectral Response, Todd M. Giles, Majeed M. Hayat, Sanjay Krishna Mar 2010

Shift Estimation Algorithm For Dynamic Sensors With Frame-To-Frame Variation In Their Spectral Response, Todd M. Giles, Majeed M. Hayat, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

This study is motivated by the emergence of a new class of tunable infrared spectral-imaging sensors that offer the ability to dynamically vary the sensor's intrinsic spectral response from frame to frame in an electronically controlled fashion. A manifestation of this is when a sequence of dissimilar spectral responses is periodically realized, whereby in every period of acquired imagery, each frame is associated with a distinct spectral band. Traditional scene-based global shift estimation algorithms are not applicable to such spectrally heterogeneous video sequences, as a pixel value may change from frame to frame as a result of both global motion …

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The Size Ellect On The Infrared Spectra Of Condensed Media Under Conditions Of Id, 2d And 3d Dielectric Confinement, Igor I. Shaganov, Tatiana S. Perova, Vasily A. Melnikov, Kevin Berwick Jan 2010

The Size Ellect On The Infrared Spectra Of Condensed Media Under Conditions Of Id, 2d And 3d Dielectric Confinement, Igor I. Shaganov, Tatiana S. Perova, Vasily A. Melnikov, Kevin Berwick

Articles

A general expression for the dielectric loss spectrum of an absorbing composite medium was obtained from a Maxwell-Garnett general equation. This expression was simplified for the cases of one, two and three dimensional dielectric confinement in both ordered and disordered thin layers, rods (wires) and spheres of absorbing medium which are considered as mesoparticles or mesoscopic molecules. This theoretical approach was verified experimentally using high purity organic liquids with strong absorption bands in the infrared range. Three organic liquids, namely benzene, chloroform and carbon disulphide, were measured in various dielectric confinement configurations using Fourier Transform Infrared (FTIR) spectroscopy with a …

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Protected Ir Input System, Kevin Ersoy Dec 2009

Protected Ir Input System, Kevin Ersoy

Electrical Engineering

The result of this project is a product that may be used to apply a digital input to a system without physically touching a device. The combination of a modulated IR signal and reflective technology produces this remote actuation. The signal emitter should produce the modulated IR light, and the receiver should continuously wait for this signal to be received. If the IR signal should encounter an obstruction causing reflection at the appropriate distance, it will be reflected directly into the receiving device. This project may be extended to include multiple duplicate systems in proximity by transmitting a modulated digital …

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Phase Shaping In The Infrared By Planar Quasi-Periodic Surfaces Comprised Of Sub-Wavelength Elements, James Ginn Jan 2009

Phase Shaping In The Infrared By Planar Quasi-Periodic Surfaces Comprised Of Sub-Wavelength Elements, James Ginn

Electronic Theses and Dissertations

Reflectarrays are passive quasi-periodic sub-wavelength antenna arrays designed for discrete reflected phase manipulation at each individual antenna element making up the array. By spatially varying the phase response of the antenna array, reflectarrays allow a planar surface to impress a non-planar phasefront upon re-radiation. Such devices have become commonplace at radio frequencies. In this dissertation, they are demonstrated in the infrared for the first time--at frequencies as high as 194 THz. Relevant aspects of computational electromagnetic modeling are explored, to yield design procedures optimized for these high frequencies. Modeling is also utilized to demonstrate the phase response of a generalized …

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Particle Filter Based Mosaicking For Forest Fire Tracking, Justin Mathew Bradley Jul 2007

Particle Filter Based Mosaicking For Forest Fire Tracking, Justin Mathew Bradley

Theses and Dissertations

Using autonomous miniature air vehicles (MAVs) is a cost-effective, simple method for collecting data about the size, shape, and location characteristics of a forest fire. However, noise in measurements used to compute pose (location and attitude) of the on-board camera leads to significant errors in the processing of collected video data. Typical methods using MAVs to track fires attempt to find single geolocation estimates and filter that estimate with subsequent observations. While this is an effective method of resolving the noise to achieve a better geolocation estimate, it reduces a fire to a single point or small set of points. …

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Quantum Dot Infrared Photodetector Fabricated By Pulsed Laser Deposition Technique, Mohammed Hegazy, Tamer Refaat, Nurul Abedin, Hani Elsayed-Ali Jan 2006

Quantum Dot Infrared Photodetector Fabricated By Pulsed Laser Deposition Technique, Mohammed Hegazy, Tamer Refaat, Nurul Abedin, Hani Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Pulsed laser deposition is used to fabricate multilayered Ge quantum-dot photodetector on Si(100). Growth was studied by reflection high-energy electron diffraction and atomic force microscopy. The difference in the current values in dark and illumination conditions was used to measure the device sensitivity to radiation. Spectral responsivity measurements reveal a peak around 2 μm, with responsity that increases three orders of magnitude as bias increases from 0.5 to 3.5 V.

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Transmission Lines For Ir Signal Routing, Tasneem Mandviwala Jan 2006

Transmission Lines For Ir Signal Routing, Tasneem Mandviwala

Electronic Theses and Dissertations

In this dissertation, the design, fabrication, and characterization of coplanar striplines, vias, and microstrip lines is investigated, from the point of view of developing interconnections for antenna-coupled infrared detectors operating in the 8- to 12-micron wavelength range. To our knowledge, no previous efforts have been made to study the performance of metallic-wire transmission lines at infrared frequencies. Both the design and fabrication of these structures present unique challenges. Because of attenuation and dispersion issues, the analytical formulas for transmission-line parameters that are valid below a few hundred GHz are not applicable in the infrared. Therefore, numerical modeling was performed to …

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Introducing Students To Communications Concepts Using Optical And Low-Power Wireless Devices, James M. Conrad, Ivan Howitt Jan 2006

Introducing Students To Communications Concepts Using Optical And Low-Power Wireless Devices, James M. Conrad, Ivan Howitt

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless communication has become an important feature for commercial products and a popular research topic within the last ten years. There are now more mobile phone subscriptions than wired-line subscriptions. Lately, one area of commercial interest has been low-cost, low-power, and short-distance wireless communication used for "personal wireless networks." Technology advancements are providing smaller and more cost effective devices for integrating computational processing, wireless communication, and a host of other functionalities. These embedded communications devices will be integrated into applications ranging from homeland security to industry automation and monitoring. They will also enable custom tailored engineering solutions, creating a revolutionary …

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Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton Jan 2006

Antenna-Coupled Infrared And Millimeter-Wave Detectors: Fabrication, Measurement And Optimization, Charles Middleton

Electronic Theses and Dissertations

Antenna-coupled detectors provide uncooled, cost-effective solutions for infrared and millimeter-wave imaging. This work describes the design, fabrication, measurement, and optimization of several types of antenna-coupled detectors for LWIR (8 - 12 µm) and 94 GHz radiation. Two types of millimeter-wave antenna-coupled detectors were fabricated and tested: a slot antenna coupled to a bolometer, and a patch antenna coupled to a SiC Schottky diode. Electromagnetic modeling of the antennas helped guide the design of antennas with better impedance matching to the detectors. Schottky diodes are discussed as detectors for millimeter-wave and infrared radiation, with the goal of increasing the cutoff frequency …

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High-Resolution Image Reconstruction From A Sequence Of Rotated And Translated Frames And Its Application To An Infrared Imaging System, Russell C. Hardie, Kenneth J. Barnard, John G. Bognar, Ernest E. Armstrong, Edward A. Watson Jan 1998

High-Resolution Image Reconstruction From A Sequence Of Rotated And Translated Frames And Its Application To An Infrared Imaging System, Russell C. Hardie, Kenneth J. Barnard, John G. Bognar, Ernest E. Armstrong, Edward A. Watson

Electrical and Computer Engineering Faculty Publications

Some imaging systems employ detector arrays that are not sufficiently dense to meet the Nyquist criterion during image acquisition. This is particularly true for many staring infrared imagers. Thus, the full resolution afforded by the optics is not being realized in such a system. This paper presents a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled rotated and translationally shifted frames. Such an image sequence can be obtained if an imager is mounted on a moving platform, such as an aircraft. Several approaches to this type of problem have been proposed in the literature. …

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