Temperature tunable metamaterial absorber at THz frequencies

Dynamic or active control over the resonance frequency of the perfect metamaterial absorbers have attracted considerable attention, and many kinds of frequency tunable absorbers have been proposed. Unfortunately, these designed absorbers have drawbacks of very small frequency tuning range as well as complex unit structure. In this paper, a simple design and large frequency change range of terahertz metamaterial absorber is investigated. The absorber structure consists of only a patterned square metallic patch and an appropriate thickness of the dielectric spacing slab on top of a metallic board. Results show that the frequency tuning range of the metamaterial absorber can be up to 80.4%, which is much greater than that of the existing absorbers (no more than 30%). The continuous shift of the resonance frequency can be explained by the temperature dependent dielectric m. Besides, we also found that the presented design strategy is a genetic method and can apply to other types of structure designs. The simple design and wide frequency tuning range of the absorbers could find potential applications in materials detection, biological sensing, and frequency selective thermal emitters.