Design of the modified cylindrical Luneberg lens antenna for millimeter wave imaging

In this paper, a modified cylindrical Luneberg lens antenna is proposed for the microwave/millimeter wave imaging applications. The proposed Luneberg lens is designed using the Teflon substrate (ε
_r
= 2.1) by making cylindrical voids of different radius along the circumference. The parameters of the designed antenna such as the directivity and the beamwidth are compared with the simple horn antenna to show the resolution enhancement using the proposed Luneburg lens. Finally, the reflectivity images of the metal patches concealed behind the Polyvinylchloride (PVC) slab are obtained using the designed Luneburg lens to show its applicability for the mm-wave imaging.