Search for dissertations about: "GTD"

Showing result 1 - 5 of 7 swedish dissertations containing the word GTD.

  1. 1. Pay tracing tools for high frequency electromagnetics simulations

    University dissertation from Stockholm : Numerisk analys och datalogi

    Author : Sandy Sefi; [2003]
    Keywords : CEM; GTD; Ray Tracing; NURBS; Software Architecture; Shadowing;

    Abstract : Over the past 20 years, the development in ComputationalElectromagnetics has produced a vast choice of methods based onthe large number of existing mathematical formulations of theMaxwell equations. None of them dominate over the others,instead they complement each other and the choice of methoddepends on the frequency range of the electromagnetic waves. READ MORE

  2. 2. Computational electromagnetics software development and high frequency modeling of surface currents on perfect conductors

    University dissertation from Stockholm : KTH

    Author : Sandy Sefi; Jesper Oppelstrup; Francisco Saez de Adana; [2005]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; High frequency approximations; Maxwell’s equations; Method of Moments; Physical Optics; Geometrical Theory of Diffraction; Extraction Extrapolation; MATHEMATICS Applied mathematics Numerical analysis; MATEMATIK Tillämpad matematik Numerisk analys;

    Abstract : In high frequency computational electromagnetics, rigorous numerical methods be come unrealistic tools due to computational demand increasing with the frequency. Instead approximations to the solutions of the Maxwell equations can be employed to evaluate th electromagnetic fields. READ MORE

  3. 3. Hybrid Methods for Computational Electromagnetics in Frequency Domain

    University dissertation from Stockholm : Numerisk analys och datalogi (NADA), (tills m KTH)

    Author : Stefan Hagdahl; Björn Engquist; Lars Pettersson; [2005]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; Geometrical Theory of Diffraction; Smooth Surface Diffraction; Boundary Element Method; Hybrid methods; Electromagnetic Scattering; MATHEMATICS Applied mathematics Numerical analysis; MATEMATIK Tillämpad matematik Numerisk analys;

    Abstract : In this thesis we study hybrid numerical methods to be used in computational electromagnetics. The purpose is to address a wide frequency range relative to a given geometry. We also focus on efficient and robust numerical algorithms for computing the so called Smooth Surface Diffraction predicted by Geometrical Theory of Diffraction (GTD). READ MORE

  4. 4. Electron Tunneling and Field-Effect Devices in mm-Wave Circuits

    University dissertation from Lund University

    Author : Mikael Egard; [2012]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; negative differential conductance oscillator; resonant tunneling diode; ultra-wideband; impulse radio; Wavelet generator; MOSFET; nanowire; high frequency characterization; Fysicumarkivet A:2012:Egard;

    Abstract : Short high-frequency electromagnetic pulses, also referred to as wavelets, are considered for use in various short-range impulse based ultra-wideband applications, such as communication, imaging, radar, spectroscopy, and localization. This thesis investigates field-effect and tunneling based semiconductor devices and their operation in millimeter-wave (mm-wave) impulse transceivers. READ MORE

  5. 5. Elastic Wave Scattering by Cracks - Interfacial Forces and High Frequency Diffraction

    University dissertation from Lund University

    Author : Gert Persson; [1992]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ultrasonic testing; Wiener-Hopf calculations; Geometrical Theory of Diffraction; edge diffracted body waves; PEDGE; two-dimensional diffraction; geometrical elastodynamic waves;

    Abstract : This thesis treats elastic wave scattering by cracks with interfacial forces. The results are of practical interest in ultrasonic testing and includes development of numerical methods used to predict such testing. First the canonical problem of two-dimensional (2-D) diffraction from a semi-infinite crack is solved. READ MORE