High-frequency penetrating radar for masonry investigation

In this paper a high-frequency large-bandwidth synthetic - aperture penetrating radar for inspecting masonry structures is described. A Continuous Wave Step Frequency (CW-SF) radar operating at 10 GHz centre frequency with 4 GHz bandwidth has been designed and built. The system is operated in a non-contact manner by mechanically moving the transmitting and receiving antennas in order to synthesize a N-dimensional aperture up to 3 m in length and 1 m in height. In spite of the fact that penetration depth decreases dramatically with increasing frequency, a penetration depth up to several tens of centimetres in masonry, that can be satisfactory in a number of applications, was observed. The high central frequency, making available very large bandwidths, provides high resolution images of the investigated structures. Laboratory tests in order to assess the performances of the system are reported.