Leaky wave circularly polarized antennas based on surface impedance modulation

The concept of modulation of surface impedance is used to design very simple leaky wave lens antennas. The antennas are circularly polarized and realized on planar surfaces. Such antennas are designed by using a holographic principle and interpreting the holographic interference pattern in terms of modulation of surface impedance. The surface impedance is reconstructing by using two different approaches. In the first one, the modulation of the reactance is provided by varying the height of a grounded dielectric slab, realizing a full dielectric lens antenna. In the second one the surface impedance is synthesized by printing a dense texture of sub-wavelength metal patches on a flat grounded dielectric slab. The latter solution results in a completely flat planar antenna. Design guidelines for both lens antennas are presented and some numerical results discussed.