Design and Measurement of Bifocal Lens Antenna for Wide Angle Beam Scanning System

In this paper a bifocal lens for wide angle beam scanning system in submillimeter wave band radar imaging system is presented. With this bifocal lens, the quasi-optical antenna can ameliorate the deterioration of multiple beams focusing with wide angle scanning in submillimeter imaging system. The paper describes the design and process of the bifocal lens at 100GHz. The simulation and measurement results demonstrate that a scanning angle of 42° (±21°) with increased difference between main lobe and side lobe by about 5dB and a flat beam waist can be achieved compared with the conventional hyperboloid lens or some aspherical lenses.