Comparative analysis of the transfer function of closed and open split-ring metamaterial slab lenses

The transfer function of some in-plane periodic split-ring metamaterial slab lenses is analyzed for several configurations across the slab. The transfer function is obtained by means of full-wave electromagnetic computations using the simulation software CST Microwave Studio, and it is compared with the transfer function obtained analytically for a continuous slab of reference. Significant differences are found in the transfer function of the analyzed structures. The closest behavior to the continuous slab lens was found for the partially open structure comprising an integer number of periods across the slab. Experiments are provided which confirms the theoretical results.

► Discrete structure of split-ring slabs imposes low-pass filter behaviour in spatial frequencies.
► Periodic rather than symmetric structures closely resembles homogeneous slabs.
► Periodic structures show improved imaging abilities with respect to symmetric structures.