DBPapers
DOI: 10.5593/SGEM2016/B13/S05.064

INFLUENCE OF DISTANCE BETWEEN THE HORN ANTENNA OF GROUND PENETRATING RADAR AND PAVEMENT SURFACE ON THE CALCULATED DIELECTRIC CONSTANT OF SURFACE LAYER

A. Porubiakova, J. Komacka
Tuesday 6 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-57-5 / ISSN 1314-2704, June 28 - July 6, 2016, Book1 Vol. 3, 505-512 pp

ABSTRACT
The air-coupled (horn) antenna of ground penetrating radar is not in the same distance above an investigated pavement surface during diagnostic. It can influence the amplitude of reflection from the pavement surface and consequently also the calculated dielectric constant of surface layer. A small study was performed to verify the differences in the calculated dielectric constant of surface layer in relation to the distance of antenna to the pavement surface. The air-coupled antenna with the central frequency of 1 GHz was used in the investigation. The reflections from four types of surfaces (dry pavement, wet pavement, metal plate and composite layer) were recorded. The distance of bottom side of antenna above the surfaces was changed in the range from 37.5 cm to 51.5 cm. It was found out the calculated dielectric constant was different and depends on the distance of antenna above the surface. The detailed analysis of amplitudes of negative and positives peaks showed the cause of variability of dielectric constant was the moderate decline of amplitudes of positive reflection peaks from pavement (dry and wet) and composite layer. Based on the results of analysis it can be stated the distance of air-coupled antenna above the surface can influence the calculated value of dielectric constant of surface layer.

Keywords: radar, antenna, surface, pavement, amplitude