Graded Index Lens Antennas Using Glide-Symmetric Metasurfaces

Sammanfattning: Lens antennas has shown potential to be used as apowerful tool for many applications in wireless communicationtoday and in the future. In this project we examine a methodof constructing graded index lens antennas using metallic glidesymmetricmetasurfaces, a method which facilitates a simplermanufacturing process and a wider bandwidth than traditionalconstruction methods. Different kinds of unit cell symmetries areexamined to determine how the geometry of a cell affects the wayswaves propagate through the medium in different directions, andcomparison between glide-symmetric unit cells and unit cellsusing a grounded plane are made. Extra attention is given to theuse of anisotropic unit cells, and different approaches to theirdesign in examined. It is found that the use of glide-symmetricunit cells closes the band gap of the structure and that usingelliptic structures creates an anisotropic material. The anisotropicproperties of the metamaterial is then shown being altered byvarying the internal dimensions of the unit cell. This propertycan thus be used to construct slim Luneburg lenses and otherlenses that require an anisotropic medium to propagate in, anda slim Luneburg lens is designed and tested.