Fluid Antenna System 

Fluid antenna system (FAS) refers to any software-controllable fluidic, dielectric or conductive structures, including but not limited to liquid-based antennas, pixel-based antennas, and meta-design antennas, that can dynamically reconfigure their shape, size, position, length, orientation, and other radiation characteristics. Thus, FAS embraces all forms of movable and non-movable flexible-position antennas. Of particular interest in physical layer design is the reconfiguration capabilities, such as the positional flexibility that FAS can offer. By near-continuously switching the antenna’s position within a predefined area to a position where the channel has desirable conditions, FAS can obtain spatial diversity and in multiuser communications, naturally make interference disappear by exploiting opportunities in fading.