Broadband Terahertz Metamaterial Absorber Based on Three-Dimensional Printable Structure and Liquid Metal

In this paper, we investigate and characterize a novel and simple approach in designing a relative broadband terahertz (THz) metamaterial absorber (MA) under 1 THz. The absorber consists of five layers of metal disc metamaterial stacked vertically and spaced by resin dielectric material. The proposed structure is easy to be realized by firstly designing micro-tunnels within the resin by three-dimensional (3D) printing technology, and then pumping in the liquid metal into the tunnels by microfluidics technique. Simulation results show that this structure exhibits an absorption above 90% in the range of 0.28-0.58 THz, exhibiting a relative broadband absorption. Furthermore, this design is sensitive to electromagnetic polarization and offers significant degrees of freedom by adjusting the parameters of the structure to shift or modify the absorber's working frequency and bandwidth. The proposed concept in realizing THz absorber holds potential applications in low-cost, rapid prototyping and easy-fabricated functional THz metamaterials.