Switchable frequency-selective rasorber/absorber based on single-sheet structure

A single-sheet structure-based switchable broadband FSR/absorber is proposed. The lossy layers I, II, and the FSS are printed along the direction of electromagnetic (EM) wave propagation (z-direction) at the top, middle, and bottom positions of the substrate, respectively. A PIN diode is used in the lossy layer II and the FSS to switch their operating states. By activating or deactivating the PIN diodes, the design can operate as either an FSR or absorber. The FSR achieves a passband with an insertion loss of 0.64 dB at 3.9 GHz, and two absorption bands with fractional bandwidth of 87.6% and 20.8%, respectively. The absorber has a wide absorption band from 1.6 to 5.4 GHz (109%). It is transparent to EM waves of orthogonal polarization. The measured and simulated results are in close agreement, which exhibits stable performance under 30 & DEG; of oblique incidence in both the xz- and yz-planes.