Foam Based Luneburg Lens Antenna at 60 GHz

An innovative technological process is investigated to easily manufacture inhomogeneous Luneburg lenses. A unique foam material is drilled and pressed to achieve the different dielectric constant needed to follow the index law inside the lens. The performance of such 60 GHz antenna is described and the antenna prototype is measured in terms of gain and radiation patterns. The results show a good efficiency (60% with a directivity of 18-19 dBi) and demonstrate the feasibility of this kind of Luneburg lens, through the use of a simple technological process. The lens with a diameter of 56 mm and a thickness of 3 mm operates in the 57-66 GHz bandwidth. The magnitude of S-11 parameter is under -10 dB in the whole bandwidth and an half-power beamwidth of 5 degrees and 5 degrees in H-plane and E-plane respectively is reached.