Method of Enhancing RIS Performance for 6G Communications: Design, Verification and Future

In this paper, we propose a horn-shaped unit-cell of reconfigurable intelligent surface (RIS) based on a PIN diode with enhancing performances for 6G communications. The unit-cell is composed of a main patch, a bull's head patch and two extended patches connected to ground. This novel structure induces a strong E-field near the sub-patch. It allows for a reduction in the length of the overall patch and a lower resonant frequency when the PIN diode is activated. Simulation results show that the reflection loss is better than −1 dB in 9.5 ~10 GHz range with the proposed horn-shaped structure. A sub-array of RIS, which consists of 4 × 4 array, fabricated and verified beam-forming capabilities in short-range wireless tests. Additionally, a RIS consisting of 4 sub-arrays was tested in a real environment. As a results, received signal strength is improved by +4 dB.