Fig. 2: Schematic diagrams and transmission amplitude spectra of three types of RISs.
From: A filtering reconfigurable intelligent surface for interference-free wireless communications
a A unit cell of the conventional stacked multilayer RIS. b A unit cell of the conventional receiver-transmitter RIS. These two types of RIS have low Q factors and wide occupied bandwidths. c A subarray of the proposed filtering RIS with a high Q factor for strong frequency-selective property and a narrow occupied bandwidth. A functional module is integrated into the subarray.
