Bifocal Reflector Antenna for a Standoff Radar Imaging System With Enhanced Field of View

A unique multireflector bifocal antenna design for real-time standoff imaging applications is presented in this work. The antenna is used in combination with a 300 GHz radar sensor to acquire images at 8 m over a large (80 × 50 cm) field of view (FoV). The increased FoV is obtained by the use of an antenna system composed by a bifocal elliptical Gregorian with an extended subreflector to allow for fast scanning of a beam spot. The scanning is achieved by the combination of the rotation and vertical tilting of a flat small secondary mirror. The design, simulations, prototype description and experimental results of a manufactured working prototype are presented.