A Single-Bit Reconfigurable Folded Reflectarray/Transmitarray Antenna

Abstract

In this study, a novel receiving-transmitting (RA-TA) metasurface unit cell is introduced for folded transmitarray/reflectarray antennas (FTAs/FRAs). The unit cell comprises two substrates with an air gap to ensure optimal transmission and integration of PIN diodes. Polarizer grids are employed for selecting desired polarization while each grid metal provides DC bias independently to a single unit cell with two PIN diodes surface-mounted and their orientation perpendicular to each other, i.e., along ±45°, respectively, enabling 1-bit phase compensation and polarization conversion. Thus, the proposed antenna achieves 1-bit reconfigurability and maintains polarization consistency with the feeding source. Additionally, unlike conventional FTAs and FRAs that necessitate a “±1” voltage configuration, the proposed unit cell offers cost-effectiveness and design simplicity by independently providing a positive voltage to each PIN diode. Thus, the unit cell finds application in FTA for 1-bit beam scanning and FRA for dual-beam operation in both the x- and y-directions, depending on voltage configurations. A 15 × 15 FRA array is fabricated and experimentally demonstrated to validate the proposed concept. This design provides potential applications in wireless communications, particularly in multiple input and multiple output (MIMO) systems.