THz broadband absorber fabricated by EHD-printing technology with high error tolerance

Terahertz (THz) devices, including the THz broadband absorbers, have attracted much attention in the recent decade. However, due to the micron-level precision requirement, the mainstream fabrication technology for THz devices still rely on complex and expensive photolithography or nanoimprinting techniques. Electrohydrodynamics (EHD) printing technology offers a novel, convenient, and cost-effective solution to this issue. A broadband THz absorber with over 90% absorption in the range of 98–353 GHz was designed and fabricated by EHD printing technology, and the inductive fishnet grid structure was used for the metasurface. The equivalent circuit model of the absorber was established based on the transmission line theory and impedance matching theory. Simulation results matched well with the theoretical and experimental results, and further demonstrated that the absorbers were polarization insensitive. Furthermore, both simulation and experiments proved that the absorption spectrum was insensitive to the fishnet grid linewidth and surface resistance, i.e., the design has high tolerance to possible fabrication errors. Therefore, the EHD printing technology can be a promising fabrication method of THz absorbers for future mass production.