Ultra-Thin Metasurface for High Gain and Beam Steering at 5G Millimeter Wave Applications

This paper illustrates the design of triple layer transmitarray, in planar shape configuration, having phase modulation capability for beam steering application at $\mathrm{f}=27 \mathrm{GHz}$. A transmitarray unit cell, comprising three layers composed of identical circular ring slots is designed. Each layer is separated by a distance $t=0.254 \mathrm{~mm}$. The aforesaid unit cell is employed as a basis element for a $13 \times 13$ planar transmitarray with 2-bit monofocal phase compensation capability. The transmitarray is fed by a standard horn antenna having an approximate gain of 10 dBi with a focal distance of $F=44.7 \mathrm{~mm}$. Simulation results show that planar transmitarray allows a $\phi_{\mathrm{BS}}=$ ±19-degree beam steering capability with a $A_{S L}=2 \mathrm{~dB}$ scan loss and $A_{\text {SLL }}=-10.6 \mathrm{~dB}$ side lobe level. About 10 dB of gain increment with respect to the standard double-ridged horn antenna is obtained for the planar transmitarray, respectively.