Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xvii, 165 p.; also includes graphics (some col.). Includes bibliographical references (p. 158-165).

Thesis (M.S.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 47-50). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 41-43). Also available on the World Wide Web.

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Electrical and Computer Engineering." Includes bibliographical references (p. 63-66).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 62-65). Also available in electronic version.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 191-196).

This master thesis is as a final project in the Division of Computer Engineering at the Department of Electrical Engineering, Linköpings University, Sweden. The purpose of the project is to design a wide frequency range programmable frequency divider used in a PLL circuit for ultra wide band system. 0.18 um tsmc CMOS technology is used in this project. A brief introduction of PLL circuits and UWB specifications are given in the report and the circuit design issue is presented. Post-layout simulation results are shown in the later part of the report. The focus of this project is to make the frequency divider work well in wide range and high speed. Therefore, how to shorten feedback circuits’ latency and how to reduce complexity of the circuits are the main problems. Logic gate merged technique is used to reduce transistor number and carefully drawing layout makes the circuit work well in post-layout simulation.

In recent years, ultra-wideband (UWB) communications has gained tremendous popularity in both research community and industry. The large bandwidth of UWB systems raises new wireless channel effects and consequently unique advantages as well as challenges to be dealt with, compared to conventional wireless systems. One of these advantages is the ability to resolve dense multipath components and use Rake combining at the receiver in order to significantly reduce the negative effects of fading. However, implementing a Rake receiver with a sufficiently large number of fingers to make use of this advantage is an evident challenge for most UWB devices with limited signal processing capabilities. A possible approach to overcome this problem is to move computational complexity from the receiver to the more powerful transmitter, which is the main focus of the present work. In this thesis, we propose two novel pre-equalization schemes for multiple- input single-output (MISO) direct-sequence ultra-wideband (DS-UWB) systems with pre-Rake combining and symbol-by-symbol detection. The first pre-equalization filter (PEF) scheme employs one PEF per transmit antenna, whereas in the second, simplified PEF (S-PEF) scheme all transmit antennas share the same PEF. For both schemes the optimum finite impulse response (FIR) and infinite impulse response (IIR) PEFs are calculated based on the minimum mean squared error (MMSE) criterion. We show that in contrast to previously proposed schemes for DS-UWB, both our proposed PEF schemes efficiently exploit the channel shortening properties of the pre-Rake filter. In particular, our proposed PEF schemes operate at the symbol level. We also show that under certain conditions the S-PEF scheme achieves the same performance as the more complex PEF scheme. Finally, we demonstrate that a single-input multiple-output (SIMO) DS-UWB system with post-Rake combining and MMSE post-equalization is the dual system to the considered MISO DS–UWB system with pre-Rake combining and MMSE pre-equalization. This uplink-downlink duality can be exploited for efficient calculation of the PEFs and for complexity reduction. Our simulation results show that the proposed PEF schemes achieve significant performance gains over pre-Rake combining without equalization even if only short PEFs are employed, and this is the case even for long UWB channel impulse responses. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In this work, Paper-based inkjet-printed Ultra-wide band (UWB) fractal antennas are presented. Three new designs, a combined UWB fractal monopole based on the fourth order Koch Snowflake fractal which utilizes a Sierpinski Gasket fractal for ink reduction, a Cantor-based fractal antenna which performs a larger bandwidth compared to previously published UWB Cantor fractal monopole antenna, and a 3D loop fractal antenna which attains miniaturization, impedance matching and multiband characteristics. It is shown that fractals prove to be a successful method of reducing fabrication cost in inkjet printed antennas while retaining or enhancing printed antenna performance.