A Single-Layer-Substrate Dual-Band Multi-Beam Reflectarray Antenna Based on Polarization Selection Technique for Sub-Terahertz Applications

A single-layer-substrate dual-band multi-beam reflectarray antenna based on polarization selection technique for sub-terahertz (sub-THz) applications is proposed in this paper. The antenna unit cell (UC) consists of two primary ring components (outer and inner) that are orthogonally nested to achieve dual-band characteristics. Furthermore, the digital coding metasurface together with the single and multi- focus phase compensation techniques, enables the antenna array to achieve four-beam radiation and dual-beam scanning in the lower and upper frequency bands. Measured results show a very wide elevation angle of up to 104 ∘ and a high aperture efficiency of 49.2% at the lower frequency of 135 GHz. At the upper frequency of 170 GHz, a low scanning loss of 1.6 dB and a high aperture efficiency of 29% are realized. Additionally, high peak gains of 19.7 dBi and 26.3 dBi are obtained for the respective bands. Therefore, the proposed sub-THz reflectarray antenna presents itself as a promising candidate for future 6G point-to-multipoint communication systems, offering large capacity, wide coverage, and high-resolution scanning capabilities.