Terahertz Aperture Synthesized Imaging With Fan-Beam Scanning for Personnel Screening

A novel active terahertz imaging scheme based on the combination of fan-beam scanning and aperture synthesized reconstruction techniques is presented. In the horizontal direction, high resolution is obtained by the narrow side of the fan-beam based on real aperture focusing with special pillbox-like quasi-optics. In the vertical direction, high resolution is achieved by the aperture synthesized focusing techniques based on the broad side of the fan-beam. Appropriate focusing algorithms are proposed both for the single-frequency 2-D case and wideband 3-D imaging. With a 0.2-THz heterodyne transceiver, a prototype imager is developed and proof-of-concept experiments are performed. The experimental results on the resolution, specular reflection, and concealed threat objects detection are given in detail, which demonstrate the performance of the proposed imaging scheme and its potential application for fast personnel screening.