Water droplets: Toward broadband metamaterial microwave absorber

A broadband metamaterial (MM) absorber based on water droplets is proposed and investigated in this paper. The proposed MM absorber is composed of a periodic array of holes drilled in the dielectric substrate which are then filled with water droplets. The absorption property of such water absorber can be tuned by manipulating the volume of the water droplets. Through optimized design, a broadband water electromagnetic (EM) wave absorber is achieved in microwaves regime, which obtains 90% absorption efficiency across the frequency band from 7.63 to 14.94 GHz. The physical mechanism of the proposed MM absorber is investigated. The absorption performance of such MM absorber is verified through both full-wave simulation and experimental measurement which coincide with each other.