No description available.

No description available.

Thesis (Ph. D - Soil, Water abd Environmental Science) - University of Arizona. / Includes bibliographical references.

Thesis (M.S.)--Ohio University, March, 1997. / Title from PDF t.p.

published_or_final_version / Civil and Structural Engineering / Doctoral / Doctor of Philosophy

No description available.

No description available.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering, 2016 / The work presented extends and contributes to the research of modelling lightning return stroke (RS) electromagnetic (EM) fields in the time domain. Although previous work in this area has focused on individual lightning electromagnetic pulse (LEMP) modelling techniques, there has not been an investigation into the strengths and weaknesses of different methods, as well as the implementation considerations of the models. This work critically compares three unique techniques (Finite Antenna, FDTD, and Single Cell FDTD) under the same ideal simulation parameters. The research presented will evaluate the EM fields in the range of 50m to 500m from the lightning channel. This range, often referred to as the near field distance, has a significant effect on lightning induced overvoltages on distribution lines, which are primarily created by the horizontal EM fields of the RS channel. These close distances have a significant effect on the model implementations, especially with the FDTD method. Each of these modelling methods is explained and tested through examples. The models are implemented in C++ and have been included in the Appendix to aid in future implementation. From the model simulations it is clear that the FDTD method is the most comprehensive model available. It allows for non-ideal ground planes, as well as complex simulation environments. However, FDTD has a number of numerical related errors that the Finite Antenna method does not suffer from. The Single Cell FDTD method is simple to implement and does not suffer from the same numerical errors as a full FDTD implementation, but is limited to simple simulation environments. This work contributes to the research field by comparing and evaluating three techniques and giving consideration to the implementation and the applicability to lightning EM simulations. / MT2017

Ho Kwok Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 107-111). / Abstracts in English and Chinese. / Content --- p.5 / Chapter 1 --- Introduction --- p.7 / Chapter 2 --- Background Theory --- p.9 / Chapter 2.1 --- Background history --- p.9 / Chapter 2.2 --- Finite Difference Time Domain Method --- p.10 / Chapter 2.2.1 --- Basic Formulation --- p.10 / Chapter 2.2.2 --- Finite Difference Expression: --- p.11 / Chapter 2.2.3 --- Courant Stability Criterion --- p.13 / Chapter 2.3 --- Absorbing Boundary Condition (PML) --- p.13 / Chapter 2.3.1 --- "Field -Splitting Modification of Maxwell's equation, TE case" --- p.14 / Chapter 2.3.2 --- Propagation of a TE Plane Wave in a PML Medium --- p.15 / Chapter 2.3.3 --- Transmission of a wave through PML-PML Interfaces --- p.19 / Chapter 2.3.4 --- PML for FDTD in 2D domain --- p.23 / Chapter 2.3.5 --- Extension to Three Dimension Case --- p.25 / Chapter 2.3.6 --- Obtaining S-parameters for General Microwave circuit --- p.26 / Chapter 2.4 --- Extended Finite Difference Time Domain Method --- p.29 / Chapter 2.4.1 --- Direct Implementation of Lumped Elements --- p.30 / Chapter 2.4.2 --- Equivalent-Source Techniques --- p.31 / Chapter 2.5 --- EMC --- p.37 / Chapter 3 --- Novel Techniques for Extended FDTD Method --- p.38 / Chapter 3.1 --- Introduction --- p.38 / Chapter 3.2 --- The Improved FDTD-SPICE Interface --- p.38 / Chapter 3.3 --- The Improved DC Bias Source --- p.48 / Chapter 3.4 --- The Improved DC Biasing Component --- p.50 / Chapter 3.5 --- Example --- p.51 / Chapter 3.6 --- Program Architecture --- p.55 / Chapter 3.7 --- Conclusion --- p.57 / Chapter 4 --- Example Design --- p.58 / Chapter 4.1 --- Introduction --- p.58 / Chapter 4.2 --- Internal Antenna Design --- p.58 / Chapter 4.2.1 --- Half-wavelength Patch --- p.58 / Chapter 4.2.2 --- Quarter-wavelength patch --- p.63 / Chapter 4.3 --- RF Power Amplifier Circuit Design --- p.73 / Chapter 4.4 --- Active Internal Antenna Design --- p.88 / Chapter 4.4.1 --- Design --- p.88 / Chapter 4.4.2 --- Surface Wave Analysis 一 Transient state analysis --- p.91 / Chapter 4.4.3 --- Surface wave analysis -AC analysis --- p.95 / Chapter 4.4.4 --- Far Field Pattern --- p.101 / Chapter 4.5 --- Conclusion --- p.105 / Chapter 5 --- Conclusion: --- p.106 / Chapter 6 --- Reference List --- p.107 / Publication --- p.111

by Wai-Chung Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 121-124). / Abstract also in Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / Table of contents / Chapter Chapter 1: --- Introduction --- p.1 / Chapter Chapter 2: --- Background Theories --- p.4 / Chapter 2.1 --- Introduction --- p.4 / Chapter 2.2 --- Maxwell's Equations --- p.5 / Chapter 2.3 --- Basic Formulation --- p.8 / Chapter 2.4 --- Plane Wave Formulation --- p.13 / Chapter 2.4.1 --- Total-Field / Scattered-Field Algorithm --- p.14 / Chapter 2.4.2 --- Pure Scattered-Field Algorithm --- p.16 / Chapter 2.4.2.1 --- Application to PEC Structures --- p.16 / Chapter 2.4.2.2 --- Application to Lossy Dielectric Structures --- p.17 / Chapter 2.5 --- Incident Plane Wave Components Generation --- p.20 / Chapter 2.6 --- Source and Termination Modeling in FD-TD model --- p.24 / Chapter 2.6.1 --- Resistive source --- p.25 / Chapter 2.6.2 --- Resistor Formulation --- p.27 / Chapter 2.7 --- PML Formulation --- p.28 / Chapter 2.7.1 --- Two-Dimensional TE Case --- p.28 / Chapter 2.7.2 --- Extension to the Full-vector Three-Dimension Case --- p.32 / Chapter 2.8 --- Time Domain Extrapolation --- p.33 / Chapter 2.8.1 --- Prony's Model --- p.34 / Chapter 2.8.2 --- Auto-regressive Model and Performance Comparison with Prony's Method --- p.36 / Chapter 2.9 --- Summary --- p.42 / Chapter Chapter 3: --- Verification of FD-TD Method --- p.43 / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Microstrip Patch Antenna: An Introduction --- p.44 / Chapter 3.2.1 --- Direct Fed Patch --- p.45 / Chapter 3.2.2 --- EMC Patch --- p.50 / Chapter 3.2.3 --- Aperture-Coupled Patch --- p.53 / Chapter 3.3 --- Verification of FD-TD: S11 Analysis --- p.55 / Chapter 3.3.1 --- Analysis of Direct Fed Rectangular Patch Antenna --- p.56 / Chapter 3.3.2 --- Analysis of EMC Patch Antenna --- p.60 / Chapter 3.3.3 --- Analysis of Aperture-Coupled Patch Antenna --- p.63 / Chapter 3.4 --- Verification of FD-TD: Radiation Pattern Analysis --- p.66 / Chapter 3.4.1 --- The Absolute and Relative Approaches --- p.67 / Chapter 3.4.2 --- The Inset Fed Patch Antenna --- p.69 / Chapter 3.5 --- Summary --- p.71 / Chapter Chapter 4: --- Space Diversity Design --- p.73 / Chapter 4.1 --- Introduction --- p.73 / Chapter 4.2 --- How Space Diversity Antenna Works --- p.74 / Chapter 4.3 --- Criteria for Evaluation and Optimization of Diversity Performance --- p.77 / Chapter 4.4 --- Simple Approach for Two-Patch Diversity Array --- p.82 / Chapter 4.4.1 --- Performance as a Function of Antenna Separation --- p.83 / Chapter 4.5 --- Novel Designs for Performance Improvement --- p.89 / Chapter 4.5.1 --- Shorting Post Isolation --- p.90 / Chapter 4.5.2 --- Offset-positioned Configuration --- p.101 / Chapter 4.6 --- Three-Patch Diversity Array --- p.106 / Chapter 4.6.1 --- Co-aligned Configurations --- p.107 / Chapter 4.6.2 --- Offset-Positioned Configurations --- p.112 / Chapter 4.7 --- Summary --- p.117 / Chapter Chapter 5: --- Conclusion --- p.118 / Appendix A: Publication --- p.121 / Appendix B: References List --- p.122