Sökning: "Antenna sources"

Visar resultat 1 - 5 av 41 avhandlingar innehållade orden Antenna sources.

1. 1. Space Geodesy Techniques: An Experimental and Theoretical Study of Antenna Related Error Sources

   Författare :R. T. Kenneth Jaldehag; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reflector antennas; signal scattering; very long baseline interferometry VLBI ; signal multipath; space geodesy; GPS error sources; geodetic networks; Global Positioning System GPS ; postglacial rebound; choke-ring antennas;

   Sammanfattning : This thesis presents work associated with antenna related error sources, as well as antenna design, in space geodesy utilizing the techniques of Very-Long-Baseline Interferometry (VLBI) and the Global Positioning System (GPS). Geodetic VLBI uses large radio telescopes, often in global networks observing at least a few times per year. LÄS MER

3. 2. Ultra Wideband Impulse Radio for Wireless Sensing and Identification

   Författare :Majid Baghaei Nejad; Li-Rong Zheng; Kari Halonen; KTH; []
   Nyckelord :Ubiquitous computing; Impulse Radio; Ultra wideband; RFID; Wireless sensor; WSN; Antenna; System-on-Package; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Ubiquitous computing and Internet-of-Things (IoT) implies an untapped opportunity in the realm of information and communication technology, in which a large number of micro-devices with communication and/or computing capabilities, provides connectivity for anything, by anyone at anytime and anywhere. Especially, these devices can be equipped with sensors and actuators that interact with our living environment. LÄS MER

4. 3. Analysis of Dipole and Patch Antennas in Cylindrical Structures

   Författare :Peter Slättman; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fourier transform; cross-section; patch; slot; arbitrary; EFIE; trough guide; cylindrical; dipole; moment method; antenna; aperture coupled;

   Sammanfattning : This thesis deals with the analysis of dipoles, patches, and aperture coupled patches located in an infinitely long cylindrical structure with arbitrary cross-section. The analysis exploits the two-dimensional nature of the structure by expanding all fields and currents in spatial harmonics along the cylinder axis, and solving the subsequent spectral two-dimensional problems by the moment method. LÄS MER

5. 4. Estimation and Performance Analysis of Wireless Multiple Antenna Communication Channels

   Författare :Mikael Coldrey; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; capacity; Wireless communications; performance bounds; distributed sources; generalized beamforming; channel estimation; MIMO; training;

   Sammanfattning : The focus of this thesis is on channel estimation in wireless communication systems that employ multiple antennas.The thesis is divided into two parts, whereof the first part addresses theproblem of parameter estimation of distributed sources. Due to, e.g. LÄS MER

7. 5. Theory and Applications of Tri-Axial Electromagnetic Field Measurements

   Författare :Roger Karlsson; Bo Thid'e; Tobia Carozzi; Gudmund Wannberg; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; polarisation; polarization; Stokes parameters; antenna; radio waves; whistler wave; SEE; direction-finding; statistics; Poynting theorem; Rymd- och plasmafysik; Space physics; Rymdfysik;

   Sammanfattning : Polarisation, which was first studied in optics, is a fundamental property of all electromagnetic fields. A convenient way to describe the polarisation of two dimensional electromagnetic fields is given by the Stokes parameters. This thesis deals with different aspects of wave polarisation and electromagnetic field measurements. LÄS MER