Capacitive Frequency‐Selective Surfaces Metamaterial Design and Microwave Absorption Characterization for 2–8 GHz Applications

The article designs a novel low‐frequency metamaterial absorber based on frequency‐selective surfaces (FSS) to address the balance of performance and structural thickness of low‐frequency electromagnetic wave absorbers. In addition, its performance mechanisms are thoroughly investigated. The proposed absorber comprises three primary layers: resistive ink, lossy dielectric, and metal backplane. The FSS design is guided by simulated equivalent circuit theory with structural parameters optimized using the Trust Region Framework. Simulation results demonstrate that the absorber achieves a reflection loss ( RL ) < −2 dB at 2 GHz and less than −4 dB across the entire C‐band, with a total thickness of only 2 mm. Further analysis of the physical mechanisms reveals that the absorber's excellent performance is primarily attributed to the capacitive components of the FSS. Experimental measurements align with simulation results, showing over 90% agreement. This study provides an effective design methodology for developing thin electromagnetic wave absorbers, offering promising prospects for applications in compact electronic systems.