Single-band tunable metasurface for thermal emitters in 5G bands

In communications, controlling the absorptivity and emissivity of the metasurface emitters is a meaningful area of research. However, the reported emitters mainly employ a continuous external energy to support the operating state, resulting in continuous energy consumption. In this work, a metasurface thermal emitter based on phasechange material Ge2Sb2Te5 (GST) is proposed and verified. This thermal emitter shows selective emission performance independent of continuous external heat source in the 26-32 GHz. Since the GST array reveals crystalline and amorphous phases, this emitter achieves a maximum emission amplitude of 0.95 and a minimum emission amplitude of 0.17. Therefore, by switching the crystalline and amorphous states of the GST array, this emitter can achieve a maximum modulation depth of 0.78. The continuous modulation of the emission performance of this transmitter is achieved through varying the annealing temperature. At the same time, since the phase transition state of GST is thermally stable (the phase transition state can remain stable even if the external thermal conditions fail), the thermal emission performance of this thermal emitter does not require continuous energy consumption to maintain. This continuously tunable, switchable mode, and thermally stable metasurface emitter has potential applications in infrared imaging, thermophotovoltaics, 5G communications, radiative cooling, and more.