Digital Metasurface Unit Cell with Tri-Polarization Operation States

This paper proposes a novel digital metasurface unit cell capable of operating in tri-polarization states. The presented unit cell consists of a receive (Rx) patch for receiving x-polarized electromagnetic waves and a transmit (Tx) patch for scattering electromagnetic waves with different polarizations and phases. By integrating four PIN diodes into the Rx patch and altering the on/off states of these diodes, the unit cell achieves reconfigurable polarization characteristics, including left-handed circular polarization (LHCP), right-handed circular polarization (RHCP), and linear polarization (LP). Simulation results indicate that at the center frequency of 5.15 GHz, the unit cell demonstrates high electromagnetic energy transmission efficiency with good cross-polarization suppression. Besides, the relative bandwidth of the unit cell is $5.8 \%$. The proposed design enables the corresponding metasurface to perform in tri-polarization states, showcasing significant potential to advance next-generation wireless communications.