Directivity enhancement of double slot Vivaldi antenna using anisotropic zero-index metamaterials

In this paper, a compact design of the ultra-wideband (UWB) highly directive double slot Vivaldi antenna (DSVA) is presented for microwave application in the frequency range of 2-10 GHz. In order to improve the directivity of the proposed DSVA, the zero index metamaterial (ZIM) unit cells are loaded on the E-plane of the antenna. It is found that the directivity of the ZIM loaded DSVA is increased by 5.5 dB as compared with the reference tapered slot Vivaldi antenna. The proposed antenna is fabricated on the FR-4 substrate and the return loss is measured using the vector network analyzer in the non-anechoic environment. Preliminary results show that the directivity of the proposed antenna is significantly increased in the frequency range of 5 to 9 GHz.