A Multibit and Frequency-Reconfigurable Reflecting Surface for RIS Applications

Intelligent reflecting surfaces, also known as reconfigurable intelligent surfaces (RISs), have currently received much attention for their applications in wireless communication. The n-bit RISs presented in the literature are restricted to a single resonance and single polarization. These shortcomings create hurdles to engage more number of users and design a low-cost system (i.e., a separate hardware is required for each desired frequency band and each polarization). However, these issues can be solved if frequency reconfigurability and multiple polarization states [i.e., transverse electric (TE) and transverse magnetic (TM)] can be achieved in one structure. This letter presents a new multibit reconfigurable reflecting surface (RRS) with frequency-reconfigurable functionality working for both TE and TM polarized waves. The proposed design is tunable between 1.8–2.3 GHz and 2.95–3.9 GHz for TE and TM polarized electromagnetic waves, respectively. To simultaneously achieve the frequency reconfigurability and phase tailoring (varied from 0
$^\circ$
to 315
$^\circ$
) in the proposed structure, the super-cell technique is used. This latter is incorporated in a phase gradient metasurface with different digital coding patterns to perform beam scanning and splitting functionalities. The simultaneous frequency reconfigurability and phase controlling for both TE and TM polarized waves make this RRS a potential candidate for future RIS and reconfigurable devices.