Ultra-Wideband Metasurface at SubTHz: Hardware Design and Reflection Optimization

In this paper, a novel ultra-wideband Reconfigurable Intelligent Surface (RIS) operating at the sub-THz frequency band is presented. The proposed design is based on the concept of the tightly coupled dipole for implementing each of the meta-surface’s unit cells. A radio-frequency (RF) switch is integrated into each of the RIS meta-elements, and by changing between its ON and OFF states, the polarization of each dipole is rotated by 180°, resulting in a 180° phase shift within a wide bandwidth. We present full-wave electromagnetic simulation and array synthesis results for the proposed RIS design, which showcase its efficient performance in terms of the operation bandwidth and beam steering capability. We also apply a reflection optimization approach to the designed 1-bit phase states for arbitrary beam pattern realization.