Although the similarities between radar imaging and diffraction tomography have been recognized, the connection between them is often surprising to practitioners in these fields. The main goal of this paper is to consider together two imaging techniques and clarify the similarities and differences that exist between them. First, Two imaging techniques are derived from Stratton-Chu formula of the inverse scattering problem, which allows a clear understanding of the relationship between the imaging equations and the imaging targets. The targets reconstructed by radar imaging are the perfectly conducting bodies, the targets reconstructed by diffraction tomography are the dielectric bodies. Then, this derivation brings out the similarities of the solution to the unlinear imaging problem which are hidden by the linear approximation method, radar imaging from high frequency asymptotic approximation, diffraction tomography from weak scattering approximation. Finally, Two imaging techniques are discribed as Fourier imaging, which is used to identify the unknown image profile as the inverse Fourier Transform of some composite function constructed from the received data signals.