A novel broadband Fabry-Perot resonator antenna with gradient index metamaterial superstrate

In this paper, a novel broadband high gain Fabry-Perot resonator antenna is proposed. This antenna is composed of a gradient index metamaterial superstrate and a U shape slot radiator backed with PEC ground plate. A single-layer FSS with the taper-sized square rings pattern is distributed on one side of planar superstrate to realize the gradient index function, which is designed to transform the spherical wave-front excited by primary source into the planar wave-front. It is demonstrated that by adding such gradient index metamaterial superstrate, the fractional 3dB gain bandwidth of this antenna can be improved to 15.4%, as compared to that of single-layer FSS with the uniform-sized square rings pattern. These results show the potential feasibility of such kind of antenna in the broadband and high directivity applications, such as the radar and communication systems.