A Fast 220GHz Real Aperture 3D Personnel Screening System with a Novel Shaped Mirror Design

Terahertz systems have attracted much attention recently in the field of public security due to the high penetration of terahertz waves through clothes and the high resolution of terahertz images. A novel real aperture terahertz personnel screening system is demonstrated in this work. This system uses a single transmitter and receiver pair together with a quasi-optical system to irradiate and collect the terahertz waves. In the quasi-optical system, a novel design of a shaped reflector used as the main mirror helps reach a satisfying focus and meanwhile keep the beam direction invariant. By using this main mirror and a hexagonal cylindrical scanning mirror, a fast horizontal scan of 0.6m field of view can be accomplished withing 10 milliseconds. The vertical scan is realized by a customized translation stage. The whole system is able to finish a whole-body scan of a person within 2.9s with a cross-section resolution of less than 8mm.