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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.
1

Tri-Band Ground Station Antenna for Earth Observation Satellites

Baggett, Brian, Parekh, S., Sinyard, David, Chandler, Brian, Morris, R. 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / The need for increased downlink data rates and bandwidth for Earth Observation (EO) missions is driving mission planners to consider Ka-Band (25.5 to 27.0 GHz) downlinks to replace or augment the existing X-Band (8.025 to 8.400 GHz) services. Future ground stations will be required to support both bands as well as S-Band (2.0-2.3) GHz telemetry and command functions. This paper discusses the inherent tradeoffs in such a design, and proposes an implementation which permits simultaneous data reception in X-Band and Ka-Band, while providing TT&C functionality at S-Band. Analytical and measured data for the implementation are provided.
2

Design of Multi Band Microwave Devices Using Coupled Line Transmission Lines

Katakam, Sri 05 1900 (has links)
Multi band technology helps in getting multiple operating frequencies using a single microwave device. This thesis presents the design of dual and tri band microwave devices using coupled transmission line structures. Chapter 2 presents the design of a novel dual band transmission line structure using coupled lines. In chapter 3, Design of a dual band branch line coupler and a dual band Wilkinson power divider are proposed using the novel dual band transmission line structure presented in the previous chapter. In chapter 4, Design of a tri band transmission line structure by extending the dual band structure is presented. The Conclusion and future work are presented in chapter 5.
3

A Tri-Band L, S, C Prime Focus Feed: Concept, Design and Performance

Melle, Christophe, Chaimbault, David, Peleau, Fabien, Karas, Alain 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / The flight test mission services need higher data rates due to increased system complexity and the need for more accurate, higher rate, and better data acquisition. The existing L or S band frequency spectrum allocation was a limiting factor to meet this increased data rate requirement. The World Radio-communication Conference (WRC 2007) attributed new additional frequency spectrum allocations in the C band for Aeronautical Mobile Telemetry (AMT). The international flight test community has taken this opportunity to immediately take advantage of the new C-band range 5091-5250MHz. This paper presents the multi-band feed product designed by the RF & Antenna Laboratory of ZODIAC DATA SYSTEMS company. This feed is foreseen to be used in prime focus configuration on any diameter parabola dish providing telemetry and tracking channels in three L, S, and C bands. Here, are described the concept and the technology achieved taking into consideration the performance and industrial constraints. Moreover, this contribution focuses on the electromagnetic simulations of radiating elements, the feed network and RF system integration. This paper is structured as follows: firstly, the objectives and the motivation for developing a prime focus feed which works in L, S, C bands are presented. In particular, the market constraints and approach to find the best solution satisfying the feed RF requirements, and mechanical constraints, such as weight, size and cost, are discussed. The second section describes the 5 step development cycle: principle and technology, design of the telemetry channels and tracking function, cohabitation of the different radiating elements, and problems of the channels isolations. The third section discusses the performance achieved using electromagnetic simulations. The fourth section talks about the integration of RF system feed. The paper concludes by discussing future work using the same concept that is applied to other telecommunication or telemetry frequency bands.
4

Conception, Réalisation et Caractérisation de papiers fonctionnels pour des applications de filtrage électromagnétique / Design, Development and Characterization of functional paper for filtering electromagnetic applications

Barros, Fabien de 19 December 2011 (has links)
Le brouillard électromagnétique dans lequel nous vivons en permanence estaujourd’hui montré du doigt car, outre les risques sanitaires qu’il pourrait engendrer, illimite l’usage de certaines technologies. L’importance des interférences entre réseauxsans fil, ou la peur du piratage sur ces mêmes réseaux, en sont deux exemples. Cetravail de thèse vise à développer un nouveau moyen de protection contre certaines deces ondes électromagnétiques. Plus spécifiquement, ce travail se focalise sur unetechnologie capable de filtrer uniquement les ondes WiFi et GSM à travers de grandessurfaces d’une habitation, comme un mur. Pour ce faire, la fonctionnalisation d’uncomposant standard des bâtiments, le papier-peint, a été étudié.L’utilisation de surfaces sélectives en fréquence a été retenue. Ces motifs sontdirectement imprimés sur du papier à l’aide d’encre conductrice et de la techniqued’impression flexographique. L’étude s’est également portée sur la réalisation de motifsde filtrage innovants. Les résultats de simulation montrent qu’ils sont capables de filtrerdeux ou trois bandes, qu’ils sont quasiment insensibles à la polarisation et à l’angled’incidence dans une plage allant de 0° à ± 80°. Le travail a ensuite permis dedémontrer la faisabilité pratique de ce concept aux stades laboratoire et industriel.Ensuite, nous avons démontré expérimentalement l’efficacité de ce concept dans lesbandes WiFi. La transmission atteint alors -30 dB. Enfin, une validation expérimentaledu produit en situation réelle a été menée, à savoir la pose du papier-peint sur du plâtre,du bois, l’influence de la colle ou encore la pose d’une couche de papier-peint décoratifpar-dessus le produit.En conclusion, les résultats pratiques obtenus confirment les résultats théoriquesestimés et, permettent à ce nouveau concept, appelé métapapier, d’être suffisammentefficace pour permettre la réduction des ondes WiFi ou GSM. / The electromagnetic smog in which we live today is nowadays a real issue because it limits the use of certain technologies and also because there are some potential health risks associated with it, even if the latter is still a controversial subject. The importance of the interferences between wireless networks or the possibility of data hacking on the same networks are two examples. The aim of this thesis is to develop a new way to protect buildings against some of these electromagnetic waves. More specifically, this work focuses on a technology able to filter only the WiFi and the GSM waves through large areas of a home, like a wall for example. To do this, the functionalization of a standard component of buildings, the wallpaper, was studied. The use of frequency selective surface (FSS) was chosen. These patterns are printed directly on paper with a conductive ink printing technology: the flexography. The study also focuses on the realization of innovative filter designs. Simulation results show that these novel FSS are able to filter two or three bands. They are almost insensitive to the polarization and to the angle of incidence in the range of 0° to ±80°. The realization feasibility of this concept in a laboratory or in industrial conditions was demonstrated. Next, an experimental demonstration of this concept in the WiFi bands was carried out. In this context, the transmission coefficient was reached -30 dB. Finally, an experimental validation of the product in real conditions of use was conducted, namely the wallpaper was put over plasterboards or over wood panels. Also, the influence of the glue on the general performances and the placement of a decorative wallpaper over the FSS wallpaper were studied. In conclusion, the practical results obtained confirm and validate the theoretical predictions of this new concept, called metapaper, and show that the practical realizations are efficient enough to allow the reduction of WiFi or GSM signals.

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