Flat Lens Antenna with Antireflection Layers Based on Artificial Dielectrics

Artificial dielectric is applied for a thin and flat lens antenna. Large effective permittivity contributes to reduce the thickness of the lens, while an arbitrary local control of permittivity allows flat profile instead of convex profile of the conventional lenses. The large permittivity, in turn, deteriorates wave matching to the air, resulting in increase of the reflection loss. Thus, the present article proposes to add antireflection layers to the lens aiming at reduction of the mismatch loss. A new design method considering multiple reflections on both surfaces of the lens has been verified to work well experimentally.