Low-power wireless communication systems require reliable and secure links, particularly in dynamic indoor environments. However, wireless links are often affected by path loss, multipath fading, blockage, interference, and unintended signal leakage towards non-legitimate receivers. Reconfigurable intelligent surfaces (RISs) provide a promising method for modifying the wireless propagation environment by controlling the phase response of reflected electromagnetic waves. This paper presents the design and MATLAB-based evaluation of a 5.8 GHz 2-bit RIS unit cell for secure and reliable wireless communication. The proposed unit cell is represented using four discrete reflection states corresponding to 0°, 90°, 180°, and 270° phase responses. A CST model of the unit-cell geometry is used to define the physical structure, while MATLAB is used to evaluate the reflection phase response, reflection magnitude response, received signal-to-noise ratio, and secrecy rate performance. The proposed RIS-assisted wireless link is compared against no-RIS and random-RIS configurations. The results show that optimised 2-bit RIS phase control can improve the received SNR at the legitimate receiver and enhance secrecy performance by increasing the signal advantage over an unintended receiver. The study demonstrates the potential of 5.8 GHz programmable RIS unit cells for secure, reliable, and energy-efficient wireless communication.

Reconfigurable intelligent surface RIS 2-bit unit cell 5.8 GHz wireless communication physical-layer security secrecy rate received SNR reliable transmission programmable metasurface.