PB-Phase-Enabled Reconfigurable Metasurface for Generating Multi-Mode Orbital Angular Momentum Waves

This study presents a reconfigurable metasurface for dynamic generation of multi-mode orbital angular momentum (OAM) waves. Based on the Pancharatnam-Berry (PB) phase principle, a meta-atom design operating from 4.25 to 7.65 GHz achieves a full 0-360° phase modulation range. Leveraging phase compensation theory, the metasurface facilitates the generation of OAM beams with topological charges of ±1 and ±2, validated by numerical simulations. A prototype reconfigurable metasurface, controlled by a multi-channel STM32-based stepper motor system, was fabricated to enable real-time and precise phase manipulation. Experimental results corroborate the expected amplitude and phase profiles of the generated OAM beams, demonstrating the feasibility of the approach. The presented reconfigurable metasurface successfully realizes dynamic multi-mode OAM generation and switching, offering a promising avenue for increasing channel capacity in OAM-based communication systems.