Tunable artificial microwave blackbodies based on metasurfaces.

Inspired by the classic hole-cavity blackbody model, we propose an open metasurface blackbody operating at microwave frequencies, whose unit cell is a dielectric resonator lying on an opaque metal plate. The resonator has a high temperature coefficient of dielectric constant, thus the blackbody can be thermally tunable. Furthermore, when the resonator is combined with ferrite, a magnetically tunable blackbody is also obtained. Absorption spectra of these two tunable blackbody unit cells are measured, and they agree very well with the simulated results. The proposed blackbodies offer a new opportunity for practical tunable microwave absorbers in applications.