A high gain and wideband directional antenna using Z-shaped near zero-index metamaterial (NZIM) resonators

In this paper, a wideband directional antenna comprising of bow-tie elements is loaded with Z-type near zero index metamaterial (NZIM) unit cells to achieve high-gain and reduced beamwidth. Both the simulation and measurement results show that the proposed antenna has gain of 6.9 dBi-9.3 dBi in the operating band (4.9 GHz-7.6 GHz), with average gain enhancement of 1.5 dB compared to the reference antenna. Also the half-power beamwidth is reduced by 32o after loading with Z-shaped ZIM. The proposed antenna can be used in point-to-point communication applications in C-band.