Frequency- and bandwidth-controllable electromagnetic absorber using 3D-printed shape memory meta-wires

A metamaterial can be used for fabricating an electromagnetic absorber by tailoring its effective permittivity and permeability.In general, a metamaterial absorber works at a specific resonant frequency, and its absorption frequency does not change after the structure is fabricated.A three-dimensionally (3D)-printed shape memory polymer (SMP) is a potential candidate for overcoming this limitation and realising reconfigurability with its fabrication versatility.In this work, we propose a frequency -and bandwidth-controllable electromagnetic absorber using 3D-printed shape memory meta-wires (SMMWs).Unlike the conventional usage of SMPs with two states, thermally deformable SMMWs have three different modes that are realised by controlling the states of each column.Multi-material additive manufacturing is used to print the SMMW, with an SMP substrate and a high-temperature filament being the materials that are printed.The high absorptivity and frequency -and bandwidth-tuning capability are numerically and experimentally demonstrated for three different modes.