A Flexible and Transparent Broadband Absorber with High Absorptance Throughout K-Band and Ka-Band

Abstract

In this paper, a flexible and transparent broadband absorber was designed, the top layer of which is a gear-like resonant pattern made of Indium Tin Oxides (ITO) film clinging to the surface of the polyethylene terephthalate (PET) dielectric layer, and the bottom surface of the PET was covered with a whole layer of ITO film. Due to the symmetry of the resonant pattern of the absorber, it has polarization insensitive characteristic. The absorptance exceeds 90% in the frequency range of 17.5-41.2 GHz. When the incident electromagnetic waves is inclined, the absorptance starts to decrease gradually, but always stays above 80% in the range of 0-45°. Finally, the equivalent permittivity, equivalent permeability and equivalent normalized impedance were deduced from the inversion of S-parameter to analyze the operating mechanism of the absorber. The simulation results show that the absorber has good and stable absorption performance in K-band (18-26.5 GHz) and Ka-band (26.5-40 GHz), and its flexible, transparent and broadband characteristics are of considerable application in the field of transparent windows and electromagnetic shielding.