Study of millimeter wave synthetic aperture imaging in near field

Passive synthetic aperture imaging system is to use an interference principle to sample the brightness temperature in the spatial domain and obtain the images by inverse Fourier transform. The current imaging algorithms are generally applied to airborne and satellite-borne observation, which are the approximate imaging algorithms using the far-field condition. But the algorithms are not satisfied for near-flied imaging, so it is necessary to find a near-field imaging algorithm. A new imaging algorithm was deduced for near-field condition from 2D synthetic aperture imaging principle by correcting the geometrical errors, and the computer simulation results of the algorithm were given. The limitations of near field algorithm were also analyzed. The analysis shows that the near-field algorithm has a better stability in the imaging of a point source compared to the far-field imaging algorithm.