Implementation of the Phase Shift Migration in MIMO-Sidelooking Imaging at Terahertz Band

In this paper, the method of phase shift migration (PSM) for multi-input-multi-output sidelooking (MIMO-SL) was developed for fast image reconstruction in terahertz (THz) band. By investigating the relationship between the “explode fields” and the echoed data recorded in the MIMO-SL system, a data reorganization method in the wavenumber domain was developed to derive the “explode fields” based on the bistatic data. It is interesting to find that the reorganized MIMO-SL data measured in a certain frequency are equivalent to the “explode fields” in other frequency (“equivalent frequency”). By deriving and applying the modified phase shift factor at the “equivalent frequency,” a comprehensive MIMO-SL-PSM algorithm was established for the first time with fast transformation in the wavenumber domain. Proof-of-principle experiments in the 0.1-THz band were performed based on an MIMO-SL prototype system. The reconstructed images for different targets with high efficiency and quality demonstrate the theoretical results and the effectiveness of the proposed algorithm.