Flexible microwave metasurface absorber with reconfigurable absorption intensity in ultra-wideband

This article proposes a flexible metasurface absorber (MA) with reconfigurable absorption intensity in an ultra-wideband spectrum. Due to the utilization of an ultrathin polyimide substrate, the MA is endowed with superior flexibility over previous rigid designs. The pattern of the MA consists of a fourfold symmetrical metal strip and four PIN diodes, which simultaneously activate multiple resonances to generate a wide operating band. By adjusting the voltage of the PIN diodes embedded in the strips, the MA can execute various stages of reconfigurable absorption intensity through varying states of ohmic loss. When the PIN diodes are off, MA is switched to a reflector. In addition, the results of the equivalent circuit simulation confirm the feasibility of the design. Finally, an MA sample is fabricated and measured, and good agreement is obtained between the measured and simulated results. The MA achieves a reconfigurable absorption intensity varies from −16.8 to 0 dB over an ultra-wide frequency range of 5.6–16.98 GHz, with relative bandwidth up to 100.8%. As expected, the designed MA features excellent characteristics both in plane and curved states.