Polarisation insensitive planar dielectric slab waveguide extended hemi-elliptical lens

The authors present the performance of a patch fed planar dielectric slab waveguide extended hemi-elliptical lens antenna. The lens is constructed using polystyrene and weighs only 90 g. The maximum lens dimensions are 11λ×13λ in the lens plane and it is 0.6λ thick. From 18 to 30 GHz the lens can handle both TM0 and TE0 signals simultaneously and at 22 GHz it can be made to generate a 1.5 dB axial ratio circularly polarised signal when fed by a linearly polarised patch antenna orientated to 38° with respect to the horizontal. The measured gain and half-power beamwidth for TM0 and TE0 excitation at 28.5 GHz are 18.5 dB (aperture efficiency of 85%), 4.1° and 18.7 dB, 4.4°, respectively, both with a −10 dB return loss bandwidth of about 10%.