6G upper mid-band independently controllable dual-polarized reconfigurable intelligent surface (RIS)

Abstract This paper presents a novel, independently controllable dual-polarized reconfigurable intelligent surface (RIS) unit cell for 6G upper mid-band ( 7.125 $7.125$ 7.125 – 24.25 GHz $24.25\,\mathrm{GHz}$ 24.25 G H z ) applications. The proposed unit cell is based on the diagonal placement of mutually orthogonal tunable radiators (loaded with varactor diodes) alongside static dual-polarized radiators. Full-wave electromagnetic simulations of the unit cell demonstrate a phase shift range of 270 ring $270^{\circ}$ 270 ∘ , a maximum reflection loss of 4.5 dB $4.5\,\mathrm{dB}$ 4.5 d B , and 61 dB $61\,\mathrm{dB}$ 61 d B cross-polarization isolation (XPI) within a 400 MHz $400\,\mathrm{MHz}$ 400 M H z frequency range centered at 15 GHz $15\,\mathrm{GHz}$ 15 G H