A Polarization-Independent Broadband Multilayer Switchable Absorber Using Active Frequency Selective Surface

In this letter, a polarization-insensitive broadband switchable absorber has been presented, which exhibits wide absorption bandwidth switching between two frequency bands ( S -band in one biasing state, and C - and X -bands in other state). The structure utilizes the circuit analog absorber concept to achieve broadband absorption, whereas switchable mechanism is obtained by implementing active p-i-n diodes in multilayer geometry. The novelty of the proposed design lies in its four-fold symmetrical configuration and simplified biasing network as compared to the earlier reported switchable absorbers. Several parametric variations have also been investigated to explain the switching and the broadband absorption mechanisms of the structure. Furthermore, a prototype has been fabricated and experimentally demonstrated under normal incidence.