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Design and Study of a New Ultra-wideband Pattern Diversity Antenna, for High-Gain ApplicationRezazadeh, Navid 02 September 2014 (has links)
A new Ultra-Wideband (UWB) pattern diversity antenna is proposed, designed and investigated in this thesis. The antenna is capable of radiating in directive and omni-directional modes. Three different versions of the design are studied to show the performance for different applications. The first design consists of a single radiating element fed from two sides by coaxial probes over a shaped ground plane. In-phase excitation of the ports produces omni-directional radiation patterns and out-of-phase excitation results in directive radiation in the boresight of the antenna. The shape of the radiator is a disk, which is modified in geometry to improve the isolation of the ports. The antenna shows impedance bandwidth from 6.8 GHz to more than 15 GHz. The second design is a dual-element version of the same antenna to equalize the radiation patterns in the E- and H-planes. The antenna requires four ports and has an impedance bandwidth from 7.4 GHz to more than 15 GHz. A microstrip power divider is then included, in the third design, which in addition to decreasing the number of extra circuits for feeding, decreases the lower frequency to 4.5 GHz, without changing the radiation patterns significantly throughout the bandwidth. A prototype of this antenna was fabricated and measured, and the results are presented. In the fifth chapter, an electromagnetic polarization filter is designed for the single element UWB antenna, to reduce the cross-polarization level. 7 dB reduction in the maximum level of cross-polarization is achieved, throughout the frequency band 8 - 11 GHz. The following chapter is dedicated to the study and performance of the microstrip-fed UWB antenna, when used as a feed for prime-focus reflectors. It is shown that the designed antenna is capable of feeding the reflector with efficiency as high as 75%, and more than 60%, over a wide bandwidth of 5.5 - 9 GHz.
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Grassland plant diversity in relation to historical and current land use /Gustavsson, Eva, January 2007 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Includes appendix of four papers and manuscripts co-authored with others. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.
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Enriching native floristic diversity in exotic tree plantation in Hong KongYu, Ming-yee. January 2007 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available in print.
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Diversity Management : Vielfalt als Ressource; betriebswirtschaftliche Begründungen /Sandner, Dominik. January 2006 (has links)
Zugl.: Wien, Wirtschaftsuniv., Diplomarbeit, 2004 u.d.T.: Sandner, Dominik: Betriebswirtschaftliche Begründungen für Diversity Management.
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A comprehensive study and critical analysis of diversity management in organizationsCantu, Cassandra A. January 2008 (has links) (PDF)
Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2008. / Includes bibliographical references.
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Managing conflict across cultures, values and identities : a case study in the South African automotive industry /Mayer, Claude-Hélène. January 2008 (has links)
Zugl.: Grahamstown, University, Diss., 2008.
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Examining the link between macrophyte diversity, bacterial diversity, and denitrification function in wetlandsGilbert, Janice M. January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Document formatted into pages; contains xiii, 234 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 June 1.
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Effectiveness of protected area management in Thailand /Maneesai, Ronasit. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 155-201). Also available on the World Wide Web.
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Emerging trends in workforce diversity /Bialy, Eugene J. January 2004 (has links)
Thesis (M.L.S.)--University of Toledo, 2004. / Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Liberal Studies degree." Bibliography: leaves 69-71.
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Diversity among plant species in an emergent wetland an initial survey of the Landingville Marsh /Shidisky, Joseph G. January 1997 (has links)
Thesis (M. Ed.)--Kutztown University of Pennsylvania, 1997. / Source: Masters Abstracts International, Volume: 45-06, page: 3071. Typescript. Abstract precedes thesis as preliminary leaves [1-2]. Includes bibliographical references (leaves 76-79).
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