Low-cost Reflective Metasurface with Rotatable Unit Elements for 5G mmW Signal Enhancement

A novel Ka-band radio frequency reflectarray is proposed to refocus the radiation fields from antennas in the near- and far zones of the reflectarray at the Ka frequency band. The forming unit-cell structure consists of two double-layered and single-layered boards. The required phase shifts are produced by circularly rotating the phase delay lines on the single-layered board with a z-shaped pattern, which makes it easy for mass production. To demonstrate the reflectarray behavior, a 21x21 reflectarray antenna operating at 28 GHz is designed. By properly arranging the array elements, the cross-polarization is reduced. The simulated results show 4% 1 dB and 7% 3 dB gain bandwidths. The maximum gain at 28 GHz is 25.6 dB, and the aperture efficiency is approximately 37.8%.