Accurate Positioning of Reinforced Using Single-Frequency CW Radar

The reinforcing steels in concrete are accurately located by means of revising the refractive index. The microstrip array antenna is used to transmit the microwave to the concrete with vertical incidence to and a 30deg angle inclination to the concrete plane respectively. The microwave frequency used is 2.4 GHz. The horizontal position of reinforcing steel is determined by the vertically incident microwave, and the vertical position of reinforcing steel is found out by the inclined incident wave. The position of reinforcing steel is corrected accurately by refractive index because of the refraction from oblique incidence. The complex permittivity of the concrete can be obtained through measuring its attenuation factor and refractive index to the microwave. The experiment results show a quite accurate location to the reinforcing steels, and the maximum error is not more than 0.6 cm.