Considerable attentions have been attracted to the implement of electromagnetic (EM) absorbing metamaterial in the past decade. Most of EM absorbing metamaterials focused on the design methods of increasing the broadband performance. However, high-efficient tunable EM absorbing metamaterials still remain a significant challenge. In this work, a 3D-printed high-efficient tunable liquid metal-based EM absorbing metamaterial was designed and demonstrated successfully. A square cavity with four gradient-depth T-shaped microchannels structure was considered as the unit cell of absorbing metamaterial. By taking advantage of the extraordinary fluidity and high conductivity of liquid metal, the high-efficient tunable capability with nearly perfect absorbance from 4.42 to 10.45 GHz and the absorbance over 95% from 3.13 to 4.44 GHz were obtained numerically and experimentally. The simulated results of absorbance agreed well with the measured ones. The designed absorbing metamaterial provides an outstanding way to achieve continuously tunable work frequency in a broadband frequency range, promoting potential application in multi-frequency microwave filters and electromagnetic shielding fields.

在过去的十年中，电磁吸收超材料的实现引起了相当多的关注。大部分电磁吸收超材料集中在提高宽带性能的设计方法上。然而，高效的可调谐EM吸收超材料仍然是一项重大挑战。在这项工作中，成功设计并演示了3D打印的高效可调谐液态金属基EM吸收超材料。具有四个梯度深度T形微通道结构的方腔被认为​​是吸收超材料的晶胞。通过利用液态金属非凡的流动性和高电导率，高效的可调谐能力在4.42 GHz至10.45 GHz范围内具有近乎完美的吸收率，在3.13至4范围内具有超过95％的吸收率。通过数值和实验获得了44 GHz。吸光度的模拟结果与实测值吻合良好。设计的吸收性超材料为在宽带频率范围内实现连续可调的工作频率提供了一种出色的方法，从而促进了在多频微波滤波器和电磁屏蔽领域的潜在应用。