A Polarization-Independent Single Band Switchable Metamaterial Absorber

In this paper, a single band switchable metamaterial absorber based on active frequency selective surface (AFSS) has been presented. The proposed design comprises of periodically arranged circular loops on which semiconductor switches (PIN diodes) are implemented. By controlling the bias voltage of the PIN diodes, the absorption frequency can be switched between two different frequency bands. Moreover, the proposed design is four-fold symmetric thereby realizing polarization-insensitive behaviour, unlike the earlier reported switchable absorbers. Finally, the structure has been fabricated, whose measured results are in good agreement with the simulated responses under normal as well as oblique incidence.