A W-band Zero Refractive Index Metamaterial for Side Lobe Reduction of Antenna

A W-band zero index metamaterial (ZIM) is proposed in this paper for reducing the side lobe level (SLL) of the antenna. The ZIM consists of a substrate and two metallic layers. The effective permittivity and permeability are near zero simultaneously, which leads to zero refractive index as well as good impedance matching. Then the antenna with the proposed ZIM cover is simulated. The results show that the SLL of E-plane and H-plane are obviously suppressed by 8.83dB and 3.16dB, respectively, and the gain also has an improvement of 1.31dB.