Research On The Near-field Imaging Of Millimeter-wave Synthetic Aperture Radiometer

Millimeter wave is between the microwave and infrared, has the advantages of them and penetrating ability. Passive millimeter wave imaging technology has obvious advantages over microwave imaging. PMW has higher spatial resolution than microwave, and better contrast of imaging than infrared. Synthetic aperture radiometer which is based on coherent signal processing is one of millimeter wave imaging system. It has high spatial resolution without mechanical scanning. In short, passive millimeter wave imaging technology using synthetic aperture has broad application prospects in the near field. The article will focus on the research on near-field imaging of millimeter wave synthetic aperture radiometer.Firstly, deriving the relationship of the visibility function and the target scene brightness temperature on the basis of synthetic aperture interferometry and millimeter wave.Secondly, near-field phase error is focusly researched, simulating millimeter-wave Synthetic aperture radiometer's near-field characteristics which includes near-field interferometry and inversion position of the scene on the impact of near-field's phase error; Then, researching near-field imaging algorithms based on the analysis of near-field characteristics, the algorithms mostly include Fourier algorithm based on phase correction and G-matrix inversion algorithm; Finally, a complete system and the flow of signal processing are presented. besides, imaging the same natural scenes with the two methods in the specific experimental conditions. Experimental results show that the two inversion methods have good imaging ability.