Two-shell circularly-layered dielectric lens antennas: Design and characterization

The paper describes a procedure for designing two-shell circularly-layered dielectric lens antennas (DLA) with radiation characteristics compatible with conventional multi-layer uniformly-layered Luneburg lens (LL) antennas. It is demonstrated that a two-shell lens with the favorable collimating capabilities can be designed using standard low-permittivity materials provided the proper selection of shells thickness. Analysis is performed in the 2-D formulation using the exact Mie-type series approach. The outlined recommendations are then validated on the example of two-shell spherical DLAs excited by a horn antenna modelled using commercial software.