Patch-fed planar dielectric slab waveguide Luneburg lens

The design of a patch-fed planar dielectric slab waveguide Luneburg lens weighing only 45 g and operated at 27 GHz in TM₀ mode is described. The measured half-power beamwidth (HPBW) for a 10.8 lambda, 12-cm diameter lens fed by a microstrip patch placed in intimate contact with the lens rim is 6.9deg with 16.8 dB gain and 10% bandwidth for -10 dB feed return loss, lens cross-polar levels were below -20 dB. The lens is also capable of operating in the TE₀ mode with similar radiation performance to that of the TM₀ mode. Here, measured HPBW and gain is 8 and 15.5 dB at 27 GHz. Unlike other planar lens arrangements, because of its ability to handle both TM₀ and TE₀ modes the lens has the potential to deal with the circularly polarised signals, this aspect is also explored.