Search for dissertations about: "High frequency radio waves"

Showing result 1 - 5 of 23 swedish dissertations containing the words High frequency radio waves.

  2. 1. Radio waves in the ionosphere : Propagation, generation and detection

    Author : Tobia Carozzi; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space Physics; rymdfysik;

    Abstract : We discuss various topics concerning the propagation, generation, and detec-tionof high-frequency (HF) radio waves in the Earth's ionosphere. With re-gardsto propagation, we derive a full wave Hamiltonian and a polarization evo-lutionequation for electromagnetic waves in a cold, stratified magnetoplasma. READ MORE

  4. 2. HBV frequency multiplier 2D arrays and application

    Author : Robin Dahlbäck; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; terahertz sources; 2D array frequency multipliers; Heterostructure Barrier Varactors HBVs ; THz; sub-millimetre waves; THz imaging; varactor frequency multipliers;

    Abstract : The utilisation of the THz spectrum ( 0.3-3 THz ) is hampered by technological difficulties to generate power at these frequencies. READ MORE

  5. 3. Opening New Radio Windows and Bending Twisted Beams

    Author : Erik Nordblad; Thomas B. Leyser; Kristof Stasiewicz; Vladimir Pavlenko; Paul A. Bernhardt; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Orbital angular momentum; Hall effect; Nonparaxial beam; Geometrical optics; High frequency radio waves; Ray tracing; Magnetic zenith effect; Ionospheric irregularities; Wave propagation; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Abstract : In ground based high frequency (HF) radio pumping experiments, absorption of ordinary (O) mode pump waves energises the ionospheric plasma, producing optical emissions and other effects. Pump-induced or natural kilometre-scale field-aligned density depletions are believed to play a role in self-focussing phenomena such as the magnetic zenith (MZ) effect, i. READ MORE

  6. 4. VLF and ULF Waves Associated with Magnetospheric Substorms

    Author : Andrew Collier; Lars Blomberg; James McKenzie; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Space physics; Subtorms; Magnetosphere; VLF waves; ULF waves; Space physics; Rymdfysik;

    Abstract : A magnetospheric substorm is manifested in a variety of phenomena observed both in space and on the ground. Two electromagnetic signatures are the Substorm Chorus Event (SCE) and Pi2 pulsations. The SCE is a Very Low Frequency (VLF) radio phenomenon observed on the ground after the onset of the substorm expansion phase. READ MORE

  7. 5. Millimetre wave waveguide enclosed grid frequency multipliers and imaging

    Author : Robin Dahlbäck; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Millimeter wave; THz imaging; THz sources; Grid; Heterostructure Barrier Var- actors HBVs ; Varactors; Array; FMCW; 2D-grid; Quasi-optical.; Frequency multipliers; Radars; sub-millimetre waves; Schottky diodes;

    Abstract : The utilisation of the THz spectrum ( 0.3-10 THz ) is hampered by fundamental difficulties in generating power at these frequencies. READ MORE