I. L. Al-Qadi and S. Lahouar, “Measuring layer thicknesses with GPR -theory to practice,” Constr. Build. Mater., vol. 19, no. 10, pp. 763–772, 2005.Google Scholar
 J. Scheer, “Radar reflectivity calibration procedures,” in Techniques of Radar Reflectivity Measurement, N. Currie, Ed. Norwood, MA: Artech House, 1984, pp. 116–119.Google Scholar
 C. Fauchard, B. Beaucamp, and L. Laguerre, “Non-destructive assessment of hot mix asphalt compaction/density with a step-frequency radar: Case study on a newly paved road,” Near Surf. Geophys., vol. 13, pp. 289–297, 2015.Google Scholar
 G. Olhoeft, “Electrical properties of rocks,” in Physical Properties of Rocks and Minerals, Y.. Touloukian, W.. Judd and R.. Roy, Eds. New York, NY: Hemisphere publishing corporation, 1989, pp. 257–329.Google Scholar
 A. Martinez and A. Byrnes, “Modeling dielectric-constant values of geologic materials: an aid to ground-penetrating radar data collection and interpretation”, Current Research in Earth Sciences, Bulletin 247, part I (http://www.kgs.ukans.edu/Current/2001/martinez/martinez1.html).
 M. Hallikainen, F. Ulaby, M. Dobson, M. El-Rayes, and L. Wu, “Microwave dielectric behavior of wet soil – part I: Empirical and experimental observations,” IEEE Trans. Geosci. Remote Sens., vol. GE-33, no. 1, pp. 25–34, 1985.Google Scholar
 R. Kedzierawski, J. -M. Le Caillec, and W. Czarnecki, “Verification of the time-reversal measurements protocol for buried object detection in the soil”, in Proc. International Radar Symposium 2013, Dresden, Germany, June 19–21, 2013, pp. 818–823.
 M. Zych, “Measuring experiment of FMCW ground penetrating radar”, in Proc. International Radar Symposium 2011, Leipzig, Germany, September 7–9, 2011, pp. 99–104.
 E. Huuskonen-Snicker, P. Eskelinen, T. Pellinen, and M. -K. Olkkonen, “A new microwave asphalt radar rover for thin surface civil engineering applications,” Frequenz, vol. 69, pp. 377–381, 2015.Google Scholar
 G. Matthaei, L. Young, and E. Jones, Microwave Filters, Impedance-Matching Networks and Coupling Structures. Norwood, MA: Artech House, 1980, pp. 247–252.Google Scholar
 F. Terman, Electronic and Radio Engineering. New York, NY: McGraw-Hill, 1955, pp. 164–165.Google Scholar
 S. Ramo and J. Whinnery, Fields and Waves in Modern Radio. New York, NY: John Wiley and Sons, 1960, pp. 430–431.Google Scholar