A zero index metamaterial lens for gain enhancement of patch antenna and H-plane horn antenna

A zero index metamaterial lens (ZIML) is proposed in this paper for antenna directivity and gain enhancement. The zero index metamaterial (ZIM) is constructed from both electric metamaterial with near-zero permittivity and magnetic metamaterial-modified split ring resonator (MSRR)-with near-zero permeability. The ZIM unit cell is numerically simulated in CST MWS. The scattering parameters show that there is a wide pass band where both permittivity and permeability are small enough to achieve wave collimation. Particularly, both of the two parameters are of the same value of 0.25, which not only obtains near-zero refractive index but also makes the relative characteristic impedance to be 1 and match that of air. A patch antenna and an H-plane horn antenna are also implemented to examine the directivity and gain enhancement ability of the ZIML. The E-plane radiation patterns are both sharpened greatly. The gain enhancement of patch antenna and H-plane horn antenna are 6.6 dB and 4.3 dB, respectively. The universality of the ZIML for both patch antenna and H-plane horn antenna indicates a more flexible application of the ZIML compared with traditional ones.