Detection of nonmetallic buried objects by a step frequency radar

An attempt was made to detect nonmetallic buried objects by means of a stepped frequency radar which uses the phase information of the returned UHF signal. After a brief discussion concerning the attenuation of the signal in the soil and the principle of operation it was demonstrated that the two 3-in ABS plastic drain pipes buried 35 cm deep in soil can be detected. The horizontal and vertical resolutions are 7 cm and 12.5 cm, respectively. The penetration is 70-90 cm.