Miniaturization of the THz Perfect Absorber Based on Various Spoof Topologies

Miniaturization of terahertz (THz) absorbers is crucial for advancing compact and efficient electromagnetic (EM) devices. This study investigates the impact of various spoof plasmon topologies T-slot, grating, and L-slot on the miniaturization and performance of THz metamaterial absorbers (MAs). The proposed designs utilize dual-ring and single-ring gold structures on a quartz spacer. Our structures demonstrate up to 15% size reduction while maintaining high absorption rates (96%–98%). The L-slot topology exhibits optimal performance with absorption peaks at 0.758 and 0.984 THz (dual ring) and 1.00 THz (single ring), compared to the conventional design’s 0.77-/1.15- and 1.14-THz resonances, respectively. Comprehensive analyses reveal that spoof structures significantly alter phase response, modify group delay characteristics, and enhance electric field distribution uniformity across the resonator surface. The coupled mode theory (CMT) model accurately predicts these behaviors with parameters extracted from simulation results.