Abstract Foliage penetrating (FOPEN) VHF/UHF SAR can image hidden man-made targets with wide-angle and ultra-wideband to achieve both range and azimuth with high resolutions. The target can be modeled by dihedral formed between its side and the ground due to the long wavelength of VHF/UHF. The paper provides the backscattering signal form of dihedral model, SAR image of man-made targets is simulated in theory and the signature library is formed which can be utilized in the subsequent stages of target detection and recognition.