Geodesic Lens Antenna With Integrated Dielectric Lens and Anisotropic Polarizer for Multibeam Enhancement and Circular Polarization in the Ka-band

This contribution presents the design of a metallic geodesic lens antenna integrated with a conformal plano-convex lens and a conformed anisotropic dielectric polarizer at its aperture, aimed at millimetre-wave applications in the Ka-band (22-40 GHz). The proposed configuration ensures high-directivity performance and circular polarization within an azimuthal coverage of ±56°. The geodesic lens is engineered with 11 input ports at one end and a continuous radiating flare at the opposite end, effectively channelling the excited electromagnetic field from each input port towards specific spatial directions, thus being capable of generating 11 different planar wavefronts in the azimuthal plane. The integration of a plano-convex dielectric lens at the flare's aperture enables the generation of a planar wavefront in the elevation plane, significantly enhancing the overall directivity of the antenna. Additionally, the integration of an anisotropic dielectric polarizer, constructed from dielectric slabs, converts the vertically polarized wave emitted by the geodesic lens into a left-handed circularly polarized wave. The antenna presents a relative bandwidth of 38.6% (AR < 3 dB) with its various components produced using additive manufacturing techniques. Experimental results show a strong correlation with simulated predictions.