Review Article

Technologies for Near-Field Focused Microwave Antennas

Figure 4

Basic geometrical configurations of different NFF planar lens antennas: (a) reflectarray, (b) transmitarray, and (c) Fresnel zone plate lens. The spherical wave radiated by the feed at interacts with the antenna layer to excite a field that is focused at .
(a)
(b)
(c)