“…In this communication model, low-power reconfigurable intelligent surfaces play a vital role [ 6 , 7 ]. According to the analysis of demands in IoT scenarios [ 8 , 9 ], reconfigurable surfaces such as active-frequency selective surfaces (AFSSs) should possess characteristics such as miniaturization, low power consumption, and high modulation efficiency when designed [ 10 , 11 , 12 ]. Therefore, the design of AFSS structures is undertaken.…”