Fig. 2: Generation of mixed coding patterns.
From: Chaotic information metasurface for direct physical-layer secure communication
a Generation of a mixed pattern by combining a chaotic pattern with a focusing pattern. b Mixed coding patterns at different time steps. c Cylindrical coordinate system utilized. d Normalized amplitude distributions of scattering fields for various values of the mixing factors. \(\theta\) and \(\varphi\) denote the polar angle and azimuthal angle of points on the observation hemisphere, respectively. e Numerical results of received signals’ constellation diagrams at different azimuth angles, for a mixing factor α = 0.469. The operational frequency is 2.47 GHz, and the normalized standard deviation of noise amplitude σ is set to 2 × 10−3.
