Search for dissertations about: "acoustic and electromagnetic waves"

Showing result 1 - 5 of 15 swedish dissertations containing the words acoustic and electromagnetic waves.

  2. 1. Design and Characterization of Functional Structures for Electromagnetic Waves

    Author : Andreas Ericsson; Teoretisk elektroteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electromagnetic scattering; functional structure; circular polarization selective structure; reflector antenna; electromagnetic absorber; radar cross section; compressive sensing; triaxial weave; homogenization; physical optics;

    Abstract : This dissertation deals with design and characterization of functional structures for scattering of electromagnetic waves. An abundance of these structures can be found in nature, such as the structural coloration in the feathers of a peacock, the scales of butterflies and the shell of scarab beetles. READ MORE

  4. 2. Dispersion Relations in Scattering and Antenna Problems

    Author : Christian Sohl; Institutionen för elektro- och informationsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; acoustic and electromagnetic waves; sum rules; scattering and absorption; causality; Herglotz functions;

    Abstract : This dissertation deals with physical bounds on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation or sum rule for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. READ MORE

  5. 3. Dispersion relations for extinction of acoustic and electromagnetic waves

    Author : Christian Sohl; Institutionen för elektro- och informationsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : This thesis deals with physical limitations on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. READ MORE

  6. 4. Computational Methods and Measurements for Direct and Inverse Scattering of Microwaves

    Author : Niklas Wingren; Institutionen för elektro- och informationsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electromagnetic scattering; computational electromagnetics; open-source software; millimeter wave imaging; nondestructive testing;

    Abstract : Electromagnetic waves are widely used in society today for a multitude of applications. Design of electromagnetic devices and applications requires accurate methods for evaluating performance, which often means modern computational methods. READ MORE

  7. 5. Spectra of elliptic operators and applications

    Author : Medet Nursultanov; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Helmholtz and Maxwell s equations; functional calculus; electromagnetic waveguide; acoustic waveguide; Sturm-Liouville operator; singular potential; asymptotics of eigenvalues; point interactions.;

    Abstract : In this thesis we consider several problems related to elliptic equations. Namely, we investigate Helmholtz and Maxwell's equations in Paper I and Sturm-Liouville spectral problem in Papers II,III. In Paper I we study time-harmonic electromagnetic and acoustic waveguide, modeled by an in�nite cylinder with a non-smooth cross section. READ MORE