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 6.9 degrees 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.