Reflection and transmission of reinforced concrete at 0-4 GHz: calculations using FDTD

This report presents, with FDTD calculated, reflection and transmission characteristics at frequencies between 0-4 GHz for 4 types of concrete specimens of which 3 specimen are reinforced concrete. The results show that reflection and transmission strongly depend on which type of reinforcement that is used. If the steel rods are thick and the lattice dense the radar waves through the material will be attenuated > 20 dB at frequencies below 1 GHz. At higher frequencies the attenuation is about 10 dB. If using thinner steel rods and wider lattice the attenuation and the influence of the steel rods decrease. Therefore the differences between a concrete and reinforced concrete can ignored at these frequencies. For these types of reinforcements the transmission attenuation is about 2.5 dB for frequencies above 250 MHz.