Holographic subsurface radar RASCAN-5

This paper describes the implementation of a holographic subsurface radar for sounding at shallow depths. The radar uses continuous signal with frequency switching and records phases of reflected signal at several operating frequencies. Two versions of the radar with frequency bandwidths 6.4-6.8 and 13.8-14.6 GHz were designed and tested. The data acquisition is accomplished by manual scanning along parallel equidistant lines. Upon acquisition, this two-dimensional interference pattern, or hologram, can be focused by the outlined Fourier-based back propagation algorithm into an image that reflects distribution of sources. Experimentally obtained and demonstrated in the paper images with plan view resolution of the order of 1 cm suggest application of the radar in civil engineering and non-destructive testing.