A tunable microwave absorption metamaterial inspired by moths evading bat detection

Abstract

Electromagnetic radiation in the current environment has become complex and uncontrollable due to the advancement of wireless technology. Traditional electromagnetic materials with fixed responses and performance after manufacturing, fail to meet the requirements for reconfigurable and multi-frequency protection. Inspired by the moth surface cilia to bend and evade bat sonar detection, our work introduces a metamaterial featuring broadband and tunable microwave absorption (MA) characteristics. In material systems, polyurethane (TPU) elastomers are used to reinforce CPLA matrices, balancing the mechanical properties and shape memory properties of 4D-printed composite materials for shape reconfigurable requirements under multi-physical fields. In structural design, we implement multi-unit encoding strategies to enlarge the dimensions of absorption regulation. In the optimization method, we provide a Deep Q-Network high-dimensional morphological intelligent optimization design method. The final 5 × 5 array achieves broadband, tunable MA effects in the 5.6–18 GHz range. Our work demonstrates a new path for electromagnetic absorption to evolve from static design to reconfigurable intelligence.