Proefschrift--Nijmegen. / Includes bibliographical references.

Proefschrift--Groningen. / Includes bibliographical references.

Proefschrift--Nijmegen. / Includes bibliographical references.

Proefschrift--Leiden.

Thesis (Honors)--College of William and Mary, 2008. / Includes bibliographical references (leaves 70-77). Also available via the World Wide Web.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologico / Made available in DSpace on 2012-10-17T09:51:16Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T01:09:44Z : No. of bitstreams: 1 149233.pdf: 1739402 bytes, checksum: f231a54ad17e1f48b42c9c54f341aefa (MD5) / O método de modelagem numérica denominado TLM (Transmission Linc Modeling) aplicado à análise de problemas bidimensionais, é o principal assunto deste trabalho. Inicialmente, mostra-se os conceitos da teoria de linhas de transmissão e o princípio de Huygens, pois eles são a base para o desenvolvimento do método TLM. A seguir, os princípios do método de Modelagem por Linhas de Transmissão em Duas Dimensões (TLM-2D) são apresentados. Finalmente, um conjunto de aplicações em microondas é desenvolvido, utilizando-se códigos computacionais baseados no TLM-2D e escritos em ForTran 90, a fim de validar o estudo. Abstract : The numerical modeling method, called 2D - TLM (Bidimensional Transmission Line Modeling) applied to the analysis of 2D electromagnetics problems, is the main topics of this work. Initially, the concepts of the Transmission - Line Theory and Huygens principle are presented, because they are the basis of the development of TLM method. The principles of 2D Transmission - Line Modeling method are presented. Finally, a set of microwave applications is developed, using computacional codes based on 2D - TLM and written in ForTran - 90, in order to validate the study.

The Transmission Line Modelling (TLM) method is applied to the electromagnetic modelling of vehicles. Implications of increasing frequencies in computer models of electromagnetic compatibility (EMC) studies are discussed. Efficient algorithms and resource management strategies are developed With a view to producing accurate results m a realistic computational run time. Theoretical aspects covered are: (1) the development and accuracy of the TLM method; (2) an improved Partial Huygens' surface for plane wave excitation; (3) an evaluation of high-performance local and global absorbing boundary conditions. Implementation aspects of TLM addressed include: (1) the effects of arithmetic precision on link line voltage and stub impedance calculations; (2) the development of an object-oriented computer code using the Object Modelling Technique; (3) methods for estimating and managing the memory requirement and run lime of simulations. It is shown that by optimizing algorithms and carefully managing resources, sufficient improvement can be made to allow relatively sophisticated models to be run on a modest desktop computer.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Recent narrow band imagery of the surface of Titan reveals a very non-uniform surface. While there are no global oceans of liquid ethane/methane as once conjectured, the imagery does suggest the possibility of seas or lakes of liquid ethane, methane, and other organic materials. If these exist, Titan could be considered a gigantic analog model of the Earth's climate system complete with land masses, moderately thick atmosphere, and large bodies of liquid. By studying the climate of Titan, we could gain further understanding of the processes and mechanisms that shape the Earth's climate. Reuse of existing technology and methods may be a way to speed development and lower costs for the global study of Titan. Surprisingly, one of the key technologies could be a Transit or Global Positioning System (GPS) descendant for use in tracking probes wandering the surface of Titan.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / Current theories concerning the surface of Titan postulate the existence of large, possibly oceanic, bodies of liquid ethane/ammonia plus various other chemicals. ESA's Huygens probe is designed to gather oceanographic data on Titan. If the postulated oceans or lakes do exist, follow up missions of an oceanographic nature will be planned. This paper provides a concept for a modified XBT (eXpendable Bathymetric Thermograph) probe design that will provide more data than just temperature as a function of depth. By judicious use of acoustic telemetering links, data on the sound speed profile and constituents of the ocean can be obtained. The exo-oceanographic data collected will have important ramifications for oceanographic studies on Earth.

In this work, two approaches for computing the near-field distribution around wind turbines are proposed, including: (1) Huygens Principle and (2) the parabolic equation technique. In order to simplify the problem, the cylinder model is utilized to represent the wind turbines and transform the problem into a two-dimensional case. To make Huygens Principle computationally tractable, several approximations are made based on the problem geometry especially modelling the cylinder as a plate. The expression of the electromagnetic field radiated by the equivalent magnetic current can be analytically solved by the error function. To verify the results, FEKO is utilized to simulate the scattering of infinitely long cylinders using periodic boundary condition (PBC). In order to solve the problem of multiple cylinders, a modified method is derived. For more accurate results, the parabolic equation (PE) technique is utilized to solve this problem, which is usually utilized to solve wave propagation problems. In this case, wide-angle approximation is used to solve the parabolic equation, which can obtain accurate results in a region of up to 45 degrees. Although these two approaches are not full-wave simulation, the calculation time is significantly reduced and the error is acceptable. To further verify the computed results by the parabolic equation technique, two commercial transceivers from Time Domain Corporation are used to measure the field distribution behind a finite-length metal pole. The frequency-domain results are obtained from the measured time-domain results using the fast Fourier transform. It is shown that the computed results by the parabolic equation technique agree well with the measurement results. / text