Some far-field radar imaging techniques (like spotlight-mode synthetic aperture radar and holography) are shown to have a tomographic formulation. For short radar-target distance (much shorter than the distance required in the far-field condition) the far-field computer aided tomography algorithm (CAT) may blur the reconstructed image. After studying first the near- field theory of some microwave imaging techniques, this paper shows that a unified near-field microwave tomography algorithm is possible. The received signal in SAR, which is a convolution between the spherical projection of the target and the emitted signal, can be interpreted as a Fourier transform of the spherical projection of the image as in near-field holography and tomography. Reconstruction of an SAR image may then be accomplished using a back projection algorithm. This study is an interchange of ideas between these different disciplines and it is a step towards a unified near-field algorithm. An optimal method can be used for combining the four polarimetric images (hv basis) to reduce speckle compared with the span image and single channel image.