A simple liquid-based metamaterial absorber, featuring a one-dimensional subwavelength grating incorporated with the saline water, has been proposed and investigated. Numerical simulations and experiments show that highly efficient (85%) and wideband (∼98% relative bandwidth) microwave absorption can be achieved. Due to the robust dielectric loss of the saline water, remarkable thermal insensitivity of the absorber was revealed, significantly outperforming the pure-water-based designs. In addition, owing to the inherent anisotropy of the one-dimensional structure, the absorber displays a distinct polarization-dependent characteristic, thus providing an efficient degree of freedom for modulating the absorption. The results are useful for developing thermally insensitive and polarization tunable metamaterial absorbers.
Jiang et al. (Fri,) studied this question.