  Extremely large aperture arrays (ELAAs) and reconfigurable intelligent
surfaces (RISs) are candidate enablers to realize connectivity goals for the
sixth-generation (6G) wireless networks. For instance, ELAAs can provide
orders-of-magnitude higher area throughput compared to what massive
multiple-input multiple-output (MIMO) can deliver through spatial multiplexing,
while RISs can improve the propagation conditions over wireless channels but a
passively reflecting RIS must be large to be effective. Active RIS with
amplifiers can deal with this issue. In this paper, we study the distortion
created by nonlinear amplifiers in both ELAAs and active RIS. We analytically
obtain the angular directions and depth of the nonlinear distortion in both
near- and far-field channels. The results are demonstrated numerically and we
conclude that non-linearities can both create in-band and out-of-band
distortion that is beamformed in entirely new directions and distances from the
transmitter.
