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Orthogonal frequency division multiplexing (OFDM) is an efficient multi-carrier modulation technique which can be combined with transmitter and receiver diversity communication systems. Maximal ratio combining (MRC) and space-time block coding (STBC) can be used in conjunction with receiver and transmitter diversity in order to increase the communication system's performance. For these systems, channel estimation and tracking must be performed since the receiver requires channel state information for decoding. In this thesis, block-type and comb-type channel estimation algorithms for OFDM systems over multipath fading channels are studied and simulated. Performance results using simulated frequency-selective channels are presented.

The complex permittivity ( )Ì and permeability ( æ) of a material determine the response of the material to electromagnetic radiation. Usually, the real parts of Ì and æ are positive for naturally occurring materials at microwave frequencies. Metamaterials are engineered media that are designed to have either a negative permittivity or permeability or both. Negative permeability and negative permittivity would cause electromagnetic waves traveling through this medium to exhibit unusual characteristics such as power flow in a direction opposite to the phase velocity. In this thesis, the wave matrix approach is used to calculate the total reflection and transmission coefficients of a multilayered structure. The method is applicable to all types of materials, including metamaterials. Several layered configurations are studied including both metamaterial and conventional dielectric layers. A MATLAB program is developed to examine the effects of frequency, angle of incidence and polarization. The results are compared to published data. Potential applications of metamaterials are also discussed.

Sun, Lei = 利用梯度超穎材料實現對電磁場的操控 / 孫磊. / "October 2010." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 64-74). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Sun, Lei = Li yong ti du chao ying cai liao shi xian dui dian ci chang de cao kong / Sun Lei.

by Suen Wai Mo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1980. / Bibliography: leaves 96-99.

by Chen Tian Wen. / Thesis submitted in: December 1998. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 84-87). / Text in English; abstract also in Chinese. / by Chen Tian Wen. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation of the Studies --- p.1 / Chapter 1.2 --- Structure of this Thesis --- p.2 / Chapter 2 --- A Brief Review on Sonoluminescence --- p.3 / Chapter 2.1 --- History of SL --- p.3 / Chapter 2.2 --- Experimental conditions and observations --- p.3 / Chapter 2.3 --- Theoretical results --- p.6 / Chapter 3 --- Normal Modes of EM Fields in Spherical Geometry --- p.12 / Chapter 3.1 --- Maxwell's Equations in Vacuum --- p.12 / Chapter 3.2 --- Normal Modes in Spherical Geometry --- p.13 / Chapter 3.2.1 --- Normal Modes in Homogeneous Dielectric Medium --- p.14 / Chapter 3.2.2 --- A Dielectric Sphere Embedded in an Ambient Dielelctric Medium --- p.17 / Chapter 3.2.3 --- Generalization to Layered Spheres --- p.18 / Chapter 4 --- Quantization of EM field and Field-atom Interaction --- p.21 / Chapter 4.1 --- Introduction --- p.21 / Chapter 4.2 --- Quantization of the EM fields --- p.22 / Chapter 4.3 --- Physical Interpretations --- p.24 / Chapter 4.4 --- Dipole Transition Rate in a Dielectric Medium --- p.26 / Chapter 4.5 --- Radiation rate of a dipole inside and outside a homogeneous sphere --- p.28 / Chapter 4.6 --- Summary --- p.45 / Chapter 5 --- SL Models as Layered Spheres --- p.49 / Chapter 5.1 --- Motivation of the Layered Sphere Model --- p.49 / Chapter 5.2 --- A small core and a thick outer layer --- p.50 / Chapter 5.3 --- A large core and a thin outer layer --- p.62 / Chapter 5.4 --- Summary --- p.68 / Chapter 6 --- Realistic Model from Numerical Hydro dynamic simulations --- p.70 / Chapter 6.1 --- The Model --- p.70 / Chapter 6.2 --- Results from Numerical Simulations --- p.73 / Chapter 6.3 --- Summary --- p.79 / Chapter 7 --- Conclusion --- p.81

Digitized by Kansas Correctional Industries

The usefulness of electromagnetic (EM) methods for mineral exploration is severely restricted by the presence of a conductive overburden. Approximately 80% of the Australian continent is covered by regolith that contains some of the most conductive clays on Earth. As a result, frequency-domain methods are only effective for near surface investigations and time-domain methods, that are capable of deeper exploration, require the measurement of very small, late-time signals. Both methods suffer from the fact that the currents in the conductive Earth layers contribute a large portion of the total measured signal that may mask the signal from a conductive target. In the search for non-layered structures, this form of geological noise is the greatest impediment to the success of EM surveys in conductive terrains. Over the years a range of data acquisition and processing techniques have been used in an effort to enhance the response of the non-layered target and thereby increase the likelihood of its detection.The combined use of a variety of survey configurations to assist exploration and interpretation is not new and is practiced regularly. The active nature of EM exploration means that the measured response is determined to a large degree by the way in which the Earth is energised. Geological structures produce different responses to different stimuli. In this work, two new methods of data combination are used to transform the measured data into a residual quantity that enhances the signature of non-layered geological structures. Based on the concept of data redundancy and tested using the results of numerical modelling, the new combinations greatly increase the signal to noise ratio for targets located in a conductive environment by reducing the layered Earth contribution. The data combinations have application to frequency-domain and time-domain EM surveys and simple ++ / interpretive rules can be applied to the residuals to extract geological parameters useful in exploration. The new methods make use of inductive loop sources and can therefore also be applied to airborne surveys.Airborne surveys present special difficulties due to the data acquisition procedures commonly used. Flight-line related artefacts such as herringbones detract from the appearance of maps and make boundary definition more difficult. A new procedure, based on the Radon transform, is used to remove herringbones from airborne EM maps and locate the conductive boundaries correctly, making interpretation more reliable and easier. In addition, selective filtering of the Radon transform data enables the enhancement or attenuation of specific linear features shown in the map to emphasise features of interest. Comparison of the Radon transform procedures with the more conventional Fourier transform methods shaves the Radon transform processing to be more versatile and less prone to distortion of the features in a map.The procedures developed in this work are applied to field data with good results.

Thesis (Ph. D.)--Ohio State University, 1980. / Includes bibliographical references (leaves 77-79). Available online via OhioLINK's ETD Center

Thesis (M. Sc.)(Geology)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.