An ultra-broadband metamaterial absorber tailored by solid-state plasma

Abstract

In this paper, an ultra-broadband metamaterial absorber (UBMA) is proposed on basis of plasma metamaterials and lumped elements. For the TE wave, the designed absorber exhibits an ultra-broadband absorption higher than 90% in the frequency regime 1.78 GHz–4.7 GHz. Nevertheless, for the TM wave, the proposed UBMA holds excellent reflection performance, whose reflection coefficient is close to 1. Furthermore, when the different solid-state plasma resonators (PRs) are excited, on the one hand, the single-band and ultra-broadband absorption switching can be realized. When only solid-state PRs along the x-axis are excited, the devised UBMA can form a strong absorption peak at 4.75 GHz whose absorptivity is 97.37%. And the absorption over 90% runs from 1.93 GHz to 4.22 GHz with only solid-state PRs along the z-axis excited (the relative bandwidth is 74.4%). On the other hand, the ultra-broadband absorption performance can be further improved. When all solid-state PRs are excited, the relative bandwidth is 90.1% (1.78–4.7 GHz).