A zoned two-layer flat lens design

In this paper we present a flat lens based on a zoned two-layer design, which provides us the freedom to simultaneously control the magnitude and phase of the transmitted wave passing through the lens. A transmission line approach is used to analyze the reflection and transmission coefficients of the proposed two-layer slab, and a two-step method is introduced to determine the distribution of the dielectric constants of the zones. The performance of the developed flat lens has been investigated, and the simulated results are shown to validate the design methodology. They also serve to demonstrate that the focal region of the lens exhibit a sub-wavelength characteristic in the transverse direction, even though it does not utilize a double-negative (DNG) material.