A novel high-gain omnidirectional antenna using near-zero-index metamaterials

Antennas applied in wireless communications are required to have omnidirectional radiation in horizontal plane and low profile. But, the low profile make the antenna challenging to obtain high horizontal gain. In this paper, we proposed a novel high gain antenna with near-zero-index metamaterial (NZIM). The horizontal gain of antenna with omnidirectional radiation is improved by 1.30 dBi. In addition, the increment of horizontal gain increases as the refractive index of NZIM unit approaches zero. It can be applied to further optimize the horizontal gain. This novel antenna has low profile (about 0.034λ) with high horizontal gain and omnidirectional radiation, which is suitable for wireless communications.