PRBFN-FAS: Fluid Antenna System Enabled by Pixel-based Reconfigurable Beamforming Networks

The fluid antenna system (FAS) is an emerging technology that has potential for use in 6G communication. However, its reliance on physical antenna movement leads to slow switching speed, failing to adapt to the dynamic wireless channels. This paper proposes a novel pixel-based reconfigurable beamforming network (PRBFN) that electronically emulates FAS functionality, referred to as a PRBFN-FAS. The core idea in the work is that shifting an antenna's physical position is equivalent to altering the excitation current vector of a multi-port antenna. Thus, we map the spatial-domain sampling of a FAS to the beamforming domain of the PRBFN-FAS, creating a one-to-one correspondence between antenna positions and beamforming states. Experimental results demonstrate that PRBFN-FAS provides the required correlation between all FAS states across a 5\% matched bandwidth. Furthermore, tests in communication system show its performance nearly identical to that of an ideal FAS.