A Cost-Effective Luneburg Lens Based on Glide-Symmetric Metasurface for 5G Applications

Sammanfattning: In this work, a cost-eective at Luneburg lens antenna operating at the Ka-band is presented.The antenna is suitable for high frequency applications in future communicationnetworks such as 5G systems due to its simple feeding, high directivity, and low loss.The lens is composed of a parallel plate structure loaded with glide-symmetric holes.The holes are tailored so that the required refractive index prole of a Luneburg lensis obtained. In order to realize the highest required refractive index, a dielectric diskis placed between the upper and lower layer of the lens. Glide symmetry is employedto provide ultra-wideband properties and increase the equivalent refractive index of theholey structure. Dierent congurations of holey glide-symmetric unit cells with dierentdielectric materials have been studied to nd a simple and cost-eective solution. Thelens is fed through eleven waveguide feeds to achieve a scanning capability of 50 in theazimuth plane. The heights of the waveguide feeds are stepped in order to match theirimpedance to the parallel plate gap. The lens is ended with a are to minimize reectionsbetween the lens and free-space.The nal design is a lens with a center frequency of 28 GHz with a 20% bandwidth.The reection coecient is below -11.5 dB and the crosstalk is below -16 dB for the fullfrequency band. The lens has a realized gain of 16.7 dBi at 28 GHz. The eciency is73% at 28 GHz with a metal loss of 19% and a dielectric loss of 1.8%.