Design and analysis of a dual-broadband microwave metasurface absorber with flexibility and transparency

A flexible, transparent and polarization-insensitive metasurface absorber (MA) with dual-broadband feature is proposed. The MA consists of absorption layer, transparent flexible polyvinyl chloride (PVC) dielectric layer, and indium tin oxide (ITO)/polyethylene terephthalate (PET) bottom plate. The dual-broadband characteristics are studied by transmission-line theory, numerical simulation and experiment. The experimental results indicate that over 90% absorptivity under the planar case is achieved in 10.85-26.01 GHz and 44.86-56.67 GHz, corresponding relative bandwidth are 82.23% and 23.26%, respectively. The light transmittance is 63.3%. Both theoretical analysis and simulated results are good accordance with the experiment. The influence of structural parameters on the dual-broadband absorption performance is studied. Moreover, the analysis of the impedance matching theory, surface current, magnetic field and electric field distributions and power loss density are given to explain the dual-band absorption mechanism. The proposed dual-broadband MA maintains good angular stability whether in planar (30 degrees) or conformal (20 degrees) cases. The MA has simple structure, high optical transparency and flexibility, it promises to be a good candidate for electromagnetic (EM) shielding room observation windows, touch panel controls, radio-frequency identification systems and transparent radio-frequency devices.