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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Development of Signal Sources for Millimeter and Submillimeter Wave Output

Kirby, Peter Lund 09 August 2007 (has links)
The objectives of this research lie in the area of millimeter and submillimeter wave signal generation and are directed into two paths that are separate, but related. The first involves the development of a W-Band oscillator using Raytheon's Metamorphic High Electron Mobility Transistor (MHEMT) substrate. The second involves the development of silicon formed rectangular waveguide to replace metallic waveguide, ultimately to be used in THz signal source circuits. An exploration of two different topologies for a W-Band oscillator design utilizing Raytheon s MHEMT substrate is presented. This material will demonstrate the reasoning behind the topology selection and the approach of the design. An evaluation of this first ever W-Band MHEMT oscillator will be presented demonstrating its performance capabilities. Finally, an oscillator design will be presented extending the first successful MHEMT W-Band design. The area of Silicon rectangular waveguide with is covered. A design approach of the silicon waveguide will be discussed. The technology used to fabricate and package the silicon waveguide will be explained. The results of the very first 400 GHz silicon waveguide will be shown and the future efforts will be covered. A silicon micromachined waveguide multiplier using an HBV diode circuit is constructed and successfully demonstrated with an output frequency of 261 GHz, showing little difference between using micromachined waveguide and metal waveguide. Lastly, a power combining frequency multiplier is developed utilizing HBV diodes with an output of 260 GHz. The input and output sections are created using branch line couplers. The results showed good power generation as compared to a single diode multiplier.
12

Microwave/millimeter wave multi-layer organic based interconnects

Pham, Anh-Vu Huynh 08 1900 (has links)
No description available.
13

Calibration of millimeter-wave radiometers with application to clear-air remote sensing of the atmosphere

Jackson, David Morris 08 1900 (has links)
No description available.
14

Analysis and design of UHF and millimetre wave radio frequency identification /

Pursula, Pekka. January 1900 (has links) (PDF)
Thesis (doctoral)--Helsinki University of Technology, 2009. / Includes bibliographical references. Also available on the World Wide Web.
15

Laboratory measurements of the millimeter wavelength opacity of phosphine (PH₃) and ammonia (NH₃) under simulated conditions for the cassini-saturn encounter

Mohammed, Priscilla Naseem. January 2005 (has links) (PDF)
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005. / Dr. Waymond R. Scott, Committee Member ; Dr. Aaron Lanterman, Committee Member ; Dr. Paul G. Steffes, Committee Chair ; Dr. Andrew F. Peterson, Committee Member ; Dr. Judith A. Curry, Committee Member. Vita. Includes bibliographical references.
16

Broadband absolute absorption measurements of atmospheric continua with millimeter wave cavity ringdown spectroscopy

Meshkov, Andrey I., January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 141-146).
17

Electron resonance in semiconductors at millimetre wavelengths

Robinson, M. L. A. January 1966 (has links)
No description available.
18

Authentification d'etiquettes RFID sans puce par des approches RF non intrusives / Chipless RFID Authentication based on a Non-Intrusive Approach

Ali, Zeshan 14 March 2019 (has links)
Dans cette thèse, le concept d'identification par radiofréquence sans puce (chipless RFID) est étendu à l'authentification où chaque étiquette doit présenter une signature unique qui ne peut jamais être reproduite même si quelqu'un tente de copier l'étiquette. À cette fin, le caractère aléatoire naturel (c’est-à-dire inhérent au processus de fabrication) ainsi que les paramètres de dimension des résonateurs sont utilisés. Un tel caractère aléatoire naturel peut produire des signatures électromagnétiques (EM) uniques, éventuellement utilisées pour l'authentification. Initialement, nous avons prouvé l’idée proposée en appliquant intentionnellement les variations dimensionnelles le long des résonateurs. Différentes valeurs des variations dimensionnelles appliquées sont utilisées pour trouver la variation minimale détectable par l'approche radar sans puce RFID. De plus, une analyse statistique a été réalisée pour calculer les taux d'erreur. Par la suite, une approche par spectrogramme est proposée pour extraire des paramètres indépendants de l’aspect (c’est-à-dire la fréquence de résonance et le facteur de qualité) des étiquettes RFID sans puce. Enfin, nous avons fabriqué plusieurs résonateurs présentant un caractère aléatoire naturel (sans aucune variation dimensionnelle appliquée) afin de caractériser la performance des étiquettes sans puce pour les applications d'authentification. Des technologies de réalisation à faible coût basées sur des circuits imprimés avec un procédé de gravure chimique et l’impression à jet d’encre par une imprimante de bureau ordinaire sont utilisées. Le caractère aléatoire naturel selon les dimensions des résonateurs est également confirmé par l'analyse microscopique à l'aide d'un microscope numérique. / In this thesis, the concept of chipless radio frequency identification (RFID) is extended to the chipless authentication where each tag has to present a unique signature that can never be reproduced even if someone tries to copy the tag. For this purpose, natural randomness (i.e., inherent in the fabrication process) along dimension parameters of resonators is utilized. Such natural randomness can produce unique electromagnetic (EM) signatures that are possibly employed for authentication. Initially, we proved the proposed idea by purposely applying the dimensional variations along the resonators. Different values of the purposely applied dimensional variations are used to find the minimum detectable variation by the chipless RFID radar approach. Additionally, a statistical analysis has been performed to calculate the error rates. Subsequently, a spectrogram approach is proposed to extract aspect-independent parameters (i.e., the frequency of resonance and quality factor) of chipless RFID tags. Finally, we fabricated numerous resonators exhibiting natural randomness (without any purposely applied dimensional variations) to characterize the potential of the chipless tags for authentication applications. Low-cost realization technologies such as printed circuit board (PCB) using chemical etching process and inkjet printing using ordinary office printer are utilized. The natural randomness along the dimensions of resonators is also confirmed by the microscopic analysis using a digital microscope.
19

Linearisation of an FM-CW 94.5 GHz millimeter-wave radar

De Wit, W. M. 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / The topic of millimeter wave radar systems is introduced. These radars are used in a wide range of applications in both the aviation and automotive field due to the resolution advantages which MMW systems have above their counterparts. MMW components are studied and characterised to improve on an existing linearisation technique. Different possible linearisation techniques are discussed and compared to choose the best possible technique for this application. This technique was developed and implemented in the existing system.
20

Deposição e caracterização de filmes de titanato de estrôncio e bário (Ba0,5Sr0,5(TiO3)) visando a sua utilização na fabricação de defasadores variáveis operando em 60 GHZ. / Deposition and characterization of barium strontium titanate thin films (Ba0,5Sr0,5(TiO3)) aiming its use in phase shifter fabrication working at 60 GHz.

Pelegrini, Marcus Vinicius 16 May 2016 (has links)
Este trabalho, realizado junto ao Grupo de Novos Materiais e Dispositivos (GNMD) pertencente ao Laboratório de Microeletrônica (LME) da Universidade de São Paulo, teve como objetivo correlacionar algumas propriedades físico-químicas de filmes finos de Ba1-XSrxTiO3 (BST), obtidos pela técnica de pulverização catódica reativa (sputtering), com os parâmetros de deposição, visando a fabricação de defasadores inteligentes operando em 60 GHz. Propriedades como cristalinidade e composição química foram estudadas e relacionadas com o tipo de substrato sobre o qual os filmes finos de BST foram depositados, e com os diversos parâmetros de deposição variados. Foi observada uma forte influência dos parâmetros de deposição, principalmente da temperatura e do tipo de substrato, na cristalinidade dos filmes. Os filmes depositados sobre cobre são mais cristalinos do que aqueles depositados sobre Si. Já a composição química dos filmes não variou significativamente, mantendo-se próxima à do alvo de sputtering utilizado, independentemente do substrato ou das condições de deposição. As propriedades elétricas dos filmes fabricados foram extraídas de capacitores de placas paralelas construídos utilizando o BST como dielétrico linear. As curvas de capacitância vs tensão a 1 MHz destes capacitores permitiram determinar uma variação de tunabilidade de até 44 %, para uma permissividade elétrica relativa de 310, valores estes compatíveis com aqueles encontrados na literatura. As propriedades elétricas dos filmes produzidos permitiram projetar um defasador de 1,3 mm2, com uma figura de mérito de 30º/dB para uma defasagem de 360º. / This work, performed at the New Materials and Devices Group (GNMD) of the Microelectronics Laboratory of the Polytechnic School of the University of São Paulo, has the objective to correlate reactive sputtered-BST thin films to its deposition parameters, aiming to produce a 60 GHz tunable phase shifter. Thin film crystallinity and stoichiometry were correlated with sputtering deposition parameters and the type of substrate. A strong influence of the sputtering parameters was observed on BST crystallinity, mainly the temperature and the type of substrate. Thin films on copper are more crystalline than on Si (100). The stoichiometry, on the other hand, did not change as function of the deposition parameters or the substrate in both cases. The thin films electrical properties were obtained by capacitance vs voltage measurements, with the BST as linear dielectric of a parallel plate capacitor. The capacitors 1 MHz C-V characterization showed tunabilities as high as 44%, for an electrical permittivity of 310. These properties allowed a phase shifter project, resulting a 1,3 mm2 device with a figure of merit of 30 º/dB for 360 º phase shift.

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