A quasi-optical antenna of passive THz imaging system for concealed-object identification

Real-time and high quality imaging is of great importance for security application in civil and military fields, especially for the detection of hidden threats carried by a person. Furthermore, passive imaging detection system based on THz radiation focuses more particular attention because of that it can perform the detection without privacy issues and doing harm to human body. This paper analyses the design of quasi-optical antenna system working at 0.1THz for passive imaging modality and the scanning mechanism. The antenna has not only an elliptical reflector to focus beam with low loss, but also the combination of conical scanning with a rotating mirror and THz detector array to realize high quality imager and quick imaging. With this system, an 8mm spatial resolution at 1m detected distance and 2D scan of the scene 40 deg horizontally and 80 deg vertically can be realized.