This paper presents the design of shaped integrated double-shell axial-symmetric lenses intended for space applications, using the ILASH lens design tool that is being developed at Instituto de Telecomunicações under ESA/ESTEC contract.
Two lens examples are thoroughly analysed in order to demonstrate the lens design tool capabilities. One example refers to a double-shell lens that is fed by an on-axis feed. The outer shell profile is optimized using Genetic Algorithm combined with the classical GO/PO approach. The second example corresponds to an integrated double-shell lens antenna for narrowband imaging applications. Results show that the obtained imaging lens produces very well defined multiple Gaussian beams, with reasonably low beam degradation at the extreme scan angles.
The double-shell lens approach for both applications is intended to maximize power transfer at the lens-air interface. The shaped outer shell is more than a simple impedance matching layer. This approach and the presented results are new and there is no alternative tool available for its design and global optimization. Method of Moments or FDTD tools are impractical for lens optimization loops.