Design of an Ultrawide-Angle Programmable Metasurface Based on Hexagonal Grid for 5G Millimeter-Wave Applications

An ultrawide-angle 1-bit programmable metasurface (PMS) for 5G millimeter-wave (mmWave) applications is proposed in this work. The PMS employs unit cells based on a receiving antenna configuration, enabling dynamic control of the reflection amplitude and phase via adjustable load states. A hexagonal grid layout is adopted to achieve higher integration density while maintaining constant inter-element spacing, thereby significantly enhancing wide-angle stability. The designed PMS maintains a stable phase difference of 180°±15° and a reflection amplitude above 0.81 under an ultrawide-angle incidence range of 0° to ±85° at a frequency of 27.06 GHz, which is located within the n257 (26.5–29.5 GHz) and n258 (24.25–27.5 GHz) bands used for critical applications such as hotspot coverage in 5G mmWave communications. To validate the proposed design, a 16×8 PMS prototype integrated with a field-programmable gate array (FPGA) was fabricated and measured. Both simulation and measurement results demonstrate that the PMS exhibits stable beam control capability over an incidence range of 0° to ±85°, supporting dynamic beam steering under different coding states as well as flexible switching between single- and dual-beam modes.