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.

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.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available in print.

Zugl.: Wien, Wirtschaftsuniv., Diplomarbeit, 2004 u.d.T.: Sandner, Dominik: Betriebswirtschaftliche Begründungen für Diversity Management.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2008. / Includes bibliographical references.

Zugl.: Grahamstown, University, Diss., 2008.

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.

Thesis (Ph. D.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 155-201). Also available on the World Wide Web.

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.

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).