Stiklo paketų ekranavimo efektyvumo tyrimas mikrobangų ruože /

The purpose of this work is to investigate microwave shielding effectiveness (SE) of modern window panes. In addition, it will be made sure of what is the main mechanism behind the electromagnetic shielding by investigating three different glasses reflection coefficient. In order to achieve these goals, shielding effectiveness of window panes and their components will be measured in semi-anechoic and anechoic chambers. Furthermore, these measurements will be done in near and far field conditions, for better comparison of results. Investigation of shielding effectiveness of three aforementioned glasses and five window panes were made in 2 GHz to 20 GHz frequency range. From these measurements it was found out that glasses with metallic layers have 20 dB higher shielding efficiencies, compared to a plain glass. Furthermore, it can be seen that shielding efficiency maximum of a single glasses is at 7.5 GHz and a minimum is at 15 GHz. This is caused by a Fabry-Perrot resonance inside the glass, which occurs at mentioned frequencies for 4 mm glass thickness. Double pane windows show promising 38 dB average microwave shielding efficiency. Also, there is only one clear SE minimum seen at 9 GHz. It differs from single glasses because of window pane structure. Lastly, triple pane windows have 51 dB average microwave shielding. High microwave SE makes them a likely candidate for home protection against harmful radiation. Research in near field conditions was made to see whether shorter distance between antennas would give more stable SE results. For this reason, distance was changed from 0 cm to 100cm. Plain and coated glasses were used for the experiment. As a result it was found out that if the distance between those antennas is below 20 cm, high error occurs because of the reactive field. At the distance higher than 40 cm, noise level exceeds coated glass SE. No further experiments would be reliable without larger sizes of the samples or inclusion of microwave absorbers. Reflection coefficient research showed that main shielding mechanism of plain and coated glasses is reflection itself. Further analysis of coated glasses showed that during Fabry-Perrot resonance, at 7.5 GHz absorption rises and it becomes higher than reflection. This is the reason why shielding effectiveness doesn‘t drop dramatically during resonance.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2016

Author dc:creator

• Bilotas, Evaldas,

Contributors dc:contributor

• Ragulis, Paulius

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

lit

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD20217500&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:20217500