AN ACCURATE IMAGING ALGORITHM FOR MILLIMETER WAVE SYNTHETIC APERTURE IMAGING RADIOMETER IN NEAR-FIELD

Abstract

Due to the fact that the imaging distance is similar to the dimension of synthetic aperture antenna in near-fleld, the Fourier imaging theory used in the traditional synthetic aperture imaging radiometer (SAIR), which is based on the far-fleld approximation, is invalid for near-fleld synthetic aperture imaging. This paper is devoted to establishing an accurate imaging algorithm for near- fleld millimeter wave SAIR. Firstly, the near-fleld synthetic aperture imaging theory is deduced and its relationship to the far-fleld imaging theory analyzed. Then, an accurate imaging algorithm based on the near-fleld imaging theory is established. In this method, the quadratic phase item and antenna pattern are taken into consideration, and the image reconstruction is performed by minimizing the Total- Variation norm of brightness temperature image, which reduces the in∞uence of the visibility observation error and improves imaging precision. Finally, the efiectiveness of the proposed imaging algorithm has been tested by means of several simulation experiments, and the superiority is also demonstrated by the comparison between it and the existing Fourier transform methods. The results demonstrate that the proposed method is an e-cient, feasible imaging algorithm for near- fleld millimeter wave SAIR.