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Multipoint antenna device
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics.
2003 In: International patent publication, no WO03/007422Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2003. no WO03/007422
URN: urn:nbn:se:uu:diva-93423OAI: oai:DiVA.org:uu-93423DiVA: diva2:166892
Available from: 2005-09-07 Created: 2005-09-07Bibliographically approved
In thesis
1. Theory and Applications of Tri-Axial Electromagnetic Field Measurements
Open this publication in new window or tab >>Theory and Applications of Tri-Axial Electromagnetic Field Measurements
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

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. A generalisation of the Stokes parameters to three dimensions is presented. The theory has been used to develop methods and systems for obtaining the polarisation parameters of electromagnetic waves. The methods can be applied for a wide range of electromagnetic fields, measured both on ground and onboard satellites. The applications include, e.g., direction-finding, polarisation analysis, radar, and several examples in the field of wireless communication. Further applications are given in the analysis of satellite data, where a whistler wave is considered. Whistlers are circularly polarised electromagnetic waves propagating in the magnetosphere along the geomagnetic field. Dispersion in the magnetospheric plasma make the whistler frequencies travel at different speeds and the signal takes the form of a chirp. From instantaneous polarisation analysis of the whistler´s magnetic wave field, the normal to the polarisation plane is obtained and found to precess around the geomagnetic field. A statistic analysis of ionospheric stimulated electromagnetic emissions (SEE) is also presented. SEE is generated by injecting a powerful high frequency radio wave into the ionosphere. It is shown that the SEE features have a statistical behaviour indistinguishable from the amplitude and phase distributions of narrow-band Gaussian noise. The results suggests that SEE cannot be explained by simple coherent processes alone. Finally, an expression for the complex Poynting theorem is derived for the general case of anharmonic fields. It is found that the complex Poynting theorem, for real fields and sources, is not a conservation law of the imaginary part of electromagnetic energy.

Place, publisher, year, edition, pages
Uppsala: Institutionen för astronomi och rymdfysik, 2005. 59 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 88
Space and plasma physics, polarisation, polarization, Stokes parameters, antenna, radio waves, whistler wave, SEE, direction-finding, statistics, Poynting theorem, Rymd- och plasmafysik
National Category
Fusion, Plasma and Space Physics
urn:nbn:se:uu:diva-5916 (URN)91-554-6327-4 (ISBN)
Public defence
2005-09-30, Polhemsalen, 10134, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 14:00
Available from: 2005-09-07 Created: 2005-09-07Bibliographically approved

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