An ultrabroadband metamaterial absorber based on remarkable magnetic coupling via constructing conductive composite resonators and magnetic gradient gyroid structure

Broadband electromagnetic absorbing is still a challenge due to the huge difference of waves properties in different frequency bands. Herein, based on the transmission-line theory, we propose an in-plane hybrid metamaterial absorber using coupled resonators and gradient gyroid structure to realise the ultrabroadband absorbing. The coupled resonators based on Ag-Cu alloy/ABS conductive composite serve as transmission lines to orient the dipolar magnetic field, while the gradient gyroid structure fabricated by FCI/PEEK composite boosts the strong induced magnetic field. The unique hybrid strategy contributes to the remarkable magnetic coupling interaction, which not only realises good bandwidth extending effect, but also demonstrates the enhancement of absorbing efficiency. Finally, the 3D-printed hybrid metamaterial absorber achieves the high-efficiency absorbing in 2.2-40 GHz due to the electromagnetic field coupling resonance and synergistic loss effect. This absorber shows promising potential in real-life application by reasons of the low-frequency broadband absorption and convenient manufacturing.