A Beam-Split Metasurface Antenna for 5G Applications

This article presents a hybrid metasurface split beam antenna for fifth-generation (5G) mobile applications at 3.5 GHz. Multi-beam antennas with high directivity are required for a 5G mobile network. It can be achieved by having an array antenna. Using an antenna array at low frequency increases the complexity and size of the whole network. Therefore, a metasurface (MS) is proposed to direct surface current and to have high gain and multibeam properties. To achieve that, a square split ring resonator (SSRR) and U-shaped unit cell metasurface is implemented as a superstrate to a single square patch antenna. The manipulation of this hybrid metasurface configuration can create opposite current flow on the unit cell and thus split the beam. The hybrid metasurface superstrate and antenna are fabricated on FR-4 ($\varepsilon \text{r}\,\,=4.4$, tan$\delta =0.02$). Results show that the antenna resonates well at 3.5 GHz, with a less than −10 dB reflection coefficient. The arrangement of the unit cells on the superstrate metasurface is able to split the current, and thus the radiation pattern beam is split into two beams in the E-plane at ± 45°. This antenna is a good candidate for future 5G Pico cell base stations in urban or suburban areas with high capacity and interferences.