A High-Speed Fluid Antenna System Using an Endfire Pixel-Based Reconfigurable Antenna

In this paper, an endfire pixel-based reconfigurable antenna (PRA) is proposed for high-speed fluid antenna systems (FASs). By optimizing the pixel connections and PIN diode states, 11 reconfigurable patterns are achieved, and their pattern covariance matrix agrees well will with that of traditional FAS with 11 ports across <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.5 \lambda$</tex>. Operating at 2.5 GHz with a bandwidth of 5%, our PRA-FAS demonstrates stable radiation, high efficiency, and its <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu s$</tex>-level reconfiguration speed overcomes the slow port switching issue in conventional FAS. Our design approaches the theoretical upper limit of channel capacity for ideal FAS, offering a solution for high-performance FAS.