Tunable microwave absorbing metamaterial composed of micro-channels filled with replaceable water solution

A novel water solution based tunable microwave absorbing metamaterial (MAM) with micro-channels was fabricated by 3D printing method. Two kinds of water solutions with different mass ratio, i.e., PEDOT:PSS/water and ethanol/water solutions, were utilized as microwave absorption media. The influence of water solutions and structural parameters on reflection loss (RL) and dielectric property were investigated. The results show that MAMs (thickness of 2.4 mm) have an effective absorption (RL ≤ -20 dB) in the frequency range of 8.38–12.4 GHz by changing water solutions with different conductivity and dielectric property. Furthermore, RL ≤ -20 dB in X band can be obtained by tuning the structural parameters of micro-channel. This study provides a feasible and novel strategy for fabricating water solution based tunable MAMs.