Sökning: "radio wave propagation"

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden radio wave propagation.

1. 1. Wireless Sensor Network and Radio Wave Propagation in Harsh Environments

   Författare :Mathias Grudén; Anders Rydberg; Erik Björnemo; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wireless Sensor Network; WISENET; Wave Propagation; Radio Communication; Harsh Environmnents; Engineering Science with specialization in Microwave Technology; Teknisk fysik med inriktning mot mikrovågsteknik;

   Sammanfattning : This licentiate thesis cover two important subjects regarding the application of wireless sensor networks (WSNs). Both subjects are related to propagation mechanisms. The first subject is what the radio channel looks like and how it behaves. LÄS MER

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

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

   Sammanfattning : 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. LÄS MER

4. 3. Radio Wave Propagation in Confined Environments - Measurements and Models

   Författare :Henrik Börjeson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; radio wave propagation multipath channels loss measurement; Electronics; Elektronik;

   Sammanfattning : This thesis deals with radio wave propagation in environments where the propagation is severely influenced by surrounding objects, mainly walls and other building structures. As an introduction, a brief description is given on propagation terms like loss, delay and dispersion along with system functions relevant for the topic. LÄS MER

5. 4. 60 GHz Wireless Propagation Channels: Characterization, Modeling and Evaluation

   Författare :Carl Gustafson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 60 GHz; mm-wave; IEEE 802.11ad; IEEE802.15.3c; Channel measurements; Channel modeling; propagation; MIMO; Beamforming; Spatial Multiplexing;

   Sammanfattning : To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. LÄS MER

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

   Författare :Erik Nordblad; Thomas B. Leyser; Kristof Stasiewicz; Vladimir Pavlenko; Paul A. Bernhardt; Uppsala universitet; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER