Time-domain approach for non-destructive assessment of embedded anomalies in architectural structures based on microwave reflectometry

The diagnosis issues of architectural structures by means of non-destructive testing are dealt through different techniques like IR thermography, ultrasonic, and other electromagnetic techniques. A non-destructive method based on microwave reflectometry technique is presented in preliminary way in its basis concept. The object of the research is to design a system able to perform subsurface survey in the first 20 centimeters in depth with a resolution less than 1 cm in architectural structures. The systems could allow fast investigation to allow an easy interpretation of the results by nonexperts personnel too. The system is based on the concept of the reflectomery measurements, in particular it consists of a VNA, an antenna/probe - operating in the frequency range of 1-6 GHz, -and a netbook with a code able to manage the VNA and to perform a real-time elaboration of the acquired response. The frequency response is transformed in the time-domain in order to locate the position of the anomalies inside the material under investigation (masonry or timber). The performances of the proposed method have been evaluated both on laboratory test samples, and on architectural structure. The suggested nondestructive method since it is fully portable, it is potentially applicable in all fields of the civil industry where it is necessary an on-site diagnostic.