Sökning: "electromagnetic absorber"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden electromagnetic absorber.

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

   Författare :Andreas Ericsson; Teoretisk elektroteknik; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

3. 2. Interstellar absorption across the electromagnetic spectrum

   Författare :Achim Tappe; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; interstellar medium ISM : general; supernova remnants Crab Nebula ; emission lines; — quasars: absorption lines;

   Sammanfattning : We report results of a multi-wavelength study of interstellar absorption in diffuse molecular clouds that lie in the direction of flat-spectrum quasars. Quasars as back-ground sources allow the measurement of Galactic interstellar absorption across the electromagnetic spectrum from mm to X-ray wavelengths. LÄS MER

4. 3. Hydrodynamic Modelling for a Point Absorbing Wave Energy Converter

   Författare :Jens Engström; Jan Isberg; Mats Leijon; Antonio Sarmento; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Ocean wave energy; Point absorber; Wave energy converter; Wave energy transport; Polychromatic wave; Linear generator; Resonance; Finite depth; Modelling; Engineering Science with specialization in Electronics; Teknisk fysik med inriktning mot elektronik;

   Sammanfattning : Surface gravity waves in the world’s oceans contain a renewable source of free power on the order of terawatts that has to this date not been commercially utilized. The division of Electricity at Uppsala University is developing a technology to harvest this energy. LÄS MER

5. 4. Wave Energy Conversion : Linear Synchronous Permanent Magnet Generator

   Författare :Oskar Danielsson; Mats Leijon; Göran Engdahl; Uppsala universitet; []
   Nyckelord :Engineering physics; Finite element method; linear synchronous generator; longitudinal end effect; permanent magnet; point absorber; offshore testing; wave power; Teknisk fysik;

   Sammanfattning : This thesis studies the electric aspects of a linear synchronous permanent magnet generator. The generator is designed for use in a wave energy converter, which determines the fundamental requirements of the generator. The electromagnetic properties of the generator are investigated with a finite element based simulation tool. LÄS MER

7. 5. Electromagnetic Simulation, Analysis and Design with Application to Antennas and Radar Absorbers

   Författare :Alireza Motevasselian; Lars Jonsson; Lars Pettersson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The present thesis considers two different subjects in the research area of electromagnetics. The first part is concerned with antenna design and the second with radar absorbers and rasorber.In the first part, a novel excitation technique for cylindrical dielectric resonator antennas is introduced to produce circular polarization. LÄS MER