Abstract:Since the effect of nonlinear phase factor and aberration which result in image blurring and resolution reducing in Millimeter wave synthetic aperture radiometer (MMW-SAR) near sensing imaging

the fractional Fourier transform (FRFT) and Radon-Wigner transform (RWT) using in diffraction imaging are introduced based on analyses the comparability between MMW-SAR passive imaging and the optical diffraction patterns. Through correlation and coordinate rotation on the time-frequency plane

the introduced algorithms reduce the impact of nonlinear phase and improve image quality. And mutual coherence function propagation equation (MCFPE) is also raised into MMW-SAR near sensing imaging

which can eliminate the fuzzy problem of imaging through twice Fourier transform and improve the imaging quality.