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In this paper, a 1-bit wideband reconfigurable intelligent surface (RIS) design operating at sub-6 band is proposed. The unit cells of the RIS surface are designed based on a three-layer stacked patch structure. Employing a 1-bit PIN diode to reconfigure the phase states, a phase difference of 𝟏𝟖𝟎𝟎 ± 𝟐𝟎𝟎 is observed over the frequency range of 4.81 – 5.77 GHz, corresponding to a 19.2% fractional bandwidth. The reflection magnitude of the unit cell is above –3 dB in the band of interest, and the cross-polarization of the scattered waves is found significantly lower than the single-patch structure. The RIS array with a dimension of 𝟖. 𝟐𝝀 × 𝟓. 𝟏𝝀 , corresponding to a 𝟏𝟔 × 𝟏𝟎 array is structured according to the proposed unit cell with good beam steering capabilities. 

This paper presents a reconfigurable intelligent surface (RIS) design and simulation aimed at enhancing beamforming and beam steering capabilities for 5G and 6G mobile communications. The proposed design introduces a 2- bit unit cell design, having four distinct phase states that can be tuned by a single varactor diode. This configuration has a 5x5 array and provides efficient operation at 23.8 GHz within the 5G New Radio (NR) frequency range 2 (FR2). The proposed RIS design demonstrates unique beam steering capabilities ranging from −60∘ to 60∘ in the azimuth plane which is crucial for extending coverage into the mm-wave coverage. The performance of the RIS is simulated using the CST 3D electromagnetic simulator, focusing on radar cross section (RCS) pattern for optimization. The simulation results reveal effective beam steering capabilities ranging from -10° to -60° and 10° to 60°, with a minimum scan loss of approximately 3 dB. The proposed RIS exhibits the high angular reciprocity that handles the incident waves up to 110∘ at an oblique 60∘ angle.