A flexible transparent absorber bandwidth expansion design based on characteristic modes

Abstract

In this paper, a flexible transparent absorber with broadband absorption is presented theoretically and demonstrated experimentally, which is composed of five layers. Based on the characteristic mode theory, the absorption bandwidth and modal significance of a narrow band absorber were analyzed with the modal radiation patterns and surface current, respectively. To expand the bandwidth, the effective modes and the positions where the resistors should be loaded were determined with the help of characteristic mode analysis. It has a broadband absorption in the frequency range of 14.3–28.3 GHz with a relative absorption bandwidth of about 65.72 %, and the corresponding absorptance is more than 90 %. Meanwhile, the optimized absorber also achieves a satisfactory absorption rate up to 45° incident angle for both TE and TM polarizations. The experimental results show excellent absorption rates, which indicates a good agreement with the simulated results.

Keywords

• Transparent absorber
• Bandwidth expansion
• Characteristic mode theory (CMT)