Effects of Unit Cell Enlargement and 1-Bit Quantization in 5G Linear Metasurface Antennas

Metasurface antennas constitute an attractive low cost, low complexity and low power alternative to phased arrays for 5G millimeter wave communications. This paper addresses the design of low complexity linear metasurface antennas with scanning capabilities, based on modulated surface impedances. In particular, it shows that with a proper design, the number of reconfigurable unit cells can be reduced up to a 50% without a significant reduction of the radiation properties of the antenna, by means of enlarging the unit cell sizes. Besides, the paper proposes a 1-bit reconfigurable unit cell and demonstrates the feasibility of 1-blt metasurface antennas, enabling the use of MEMS switches for loss reduction, scanning stability improvement and for simplifying the interface with digital circuitry. Finally, cell enlargement and 1-bit quantization are jointly assessed, revealing that their effects are cumulative and that in the case of 1-bit solutions, the unit cell dimensions must be carefully selected.