MULTIOBJECTIVE OPTIMIZATION AND DESIGN OF A LUNEBERG LENS ANTENNA WITH MULTIBAND MULTI-POLARIZED FEED-SYSTEM

A general multiobjective optimization and design procedure of a Luneberg lens antenna (LLA) with a compact multiband multi-polarized feed-system for a broadband satellite communication terminal is presented. The LLA utilizes a compact multiband feed horn, consisting of an inner dielectric loaded circular horn for the K/Ka-band (dual-circular polarization) and a coaxial waveguide with axially corrugated flange for the Ku-band (dual-linear polarization). Measurements show good agreement with simulations. Moreover, an efficient multiobjective evolutionary algorithm based on decomposition (MOEA/D) with differential evolution operator and objective normalization technique is firstly coupled with the vector spherical wave function expansions (VSWE) for the optimal design of a 7-layer 650 mm diameter LLA, which provides higher aperture efficiency at Ku/K/Ka-band simultaneously. The frequency dependence of the LLA is also investigated. Finally, the gain and sidelobe level of a 5-layer design are jointly evaluated and compared with previous works. The proposed design procedure provides much better radiation performances and greater design freedom to the designers, as a group of Pareto-optimal LLA solutions can be obtained with just one simulation.