Selective wave-transmitting absorber through combined metasurfaces

Abstract

Selective wave-transmitting absorbers (STAs), which have one or more narrow transmission bands among a wide absorption band are often demanded in wireless communication and stealth technology. They can be used in many applications such as reducing antennas' radar cross section, reducing the coupling between different systems and improving anti-jamming capability. However it is difficult to realize STAs utilizing conventional microwave absorber approach. Here, in this presentation we propose a new method that utilizing combined metasurfaces with different polarization dependent characteristics to circumvent this problem. The whole design composes of an electromagnetic polarization rotator and a wideband microwave metasurface absorber. In the wave-transmitting band the polarization rotator produces a cross polarization output, while outside the band it preserves the polarization of the incidence. The metasurface absorber works for certain linear polarization with an absorption band wider than the wave-transmitting band. When combining these two metasurfaces properly, the whole structure could behave as a wideband absorber with certain frequency transmit window. The polarization rotator, metasurface absorber and the combined structure are schematically demonstrates in Fig. 1, where, the left one indicates the polarization rotator composed of a chiral structure with patterned metallic films on both sides of a dielectric substrate, and the right one is the metasurface absorber made of a resistance loaded metallic wire on top of a dielectric substrate connecting through two conducting via holes to the short metallic wire at the backside. Their performance are simulated by employing full-wave electromagnetic solver, and verified through experimental measurement carried out on a fabricated prototype. Both simulated and measured results are compared in Fig. 2, which clearly demonstrates a transmission window around 10.6 GHz, together with a broadband absorption across the X band. Detailed description of the design and analysis of the working mechanism will be given in the presentation.