Design of an ultra-wideband flexible optically transparent metamaterial absorber with wide-angle and polarization stability

In this paper, an ultra-wideband, flexible, and optically transparent metamaterial absorber (MA) is proposed. The MA is devised from an Indium Tin Oxide (ITO) resistive film on a flexible transparent polyethylene terephthalate (PET) substrate, which ensures reliable performance on curved surfaces. Remarkably, The MA features stable absorption across a frequency range of 3.93 GHz to 27.45 GHz, achieving an absorption bandwidth of 149.9 % that encompasses the entire C-, X-, Ku-, and K-bands. Moreover, the proposed MA exhibits polarization insensitivity and stability under incidence angles up to 60°, achieving a 10 dB reduction in radar cross section (RCS) for both planar and curved configurations. Equivalent circuit model theory and impedance matching theory, as well as further discussion of current and field distributions, are undertaken to elucidate the underlying physical mechanisms. Subsequently, a prototype is fabricated and experimentally tested, with the measured results closely aligning with simulation results, thereby confirming the absorber’s robust absorption capabilities and applicability in microwave stealth applications.