A passive THz imaging system based on the crank-rocker mechanism

A novel passive single-channel THz imaging system employing a Cassegrain antenna of 390 mm in diameter and Schottky diodes as detecting part, and the cooperation of a high-speed line scanning mirror driven by a crank-rocker mechanism and a frame scanning mirror as two-dimensional optical-mechanical scanning part is described in this paper. The single frame imaging time of the system is only 20s, the field of view (FOV) is 30° × 36°, and the angle resolution is up to 0.6°. The experimental results show that the low cost, simple structure and efficient system can clearly image the human body, and effectively detect dangerous items concealed under the clothes.