Preparation of a double-layer bionic bamboo structure absorber based on CB/PLA-TPU composites and its broadband microwave absorption characteristics

The study of the mechanical characteristics and microwave absorption capabilities of multifunctional composite materials in complex environments has attracted considerable interest in recent years. Inspired by the structure of bamboo in nature, a novel double-layer microwave absorber structure, a CB/PLA-TPU composite bionic bamboo joint’s structure, was conceived and manufactured for this investigation. This structure ingeniously integrates the load-bearing attributes of bamboo joints with the microwave absorption qualities of CB composites. At the material level, enhancing the CB particle content enhances the matrix's folds and defects, thereby improving its dielectric polarization loss capacity. An effective absorption bandwidth of 3.84GHz was achieved, with a minimum reflection loss of −60.24dB at a 2.58mm thickness and a 9.2GHz frequency. The bionic bamboo absorber's unit structure is meticulously engineered, with experimental simulations validating its performance. According to the findings, the structure attains a 10.03GHz broadband absorption and a yield strength of 11.6MPa. It maintains broadband absorption capabilities above 9GHz even at oblique incidence angles for TM polar wave (0-60°) and TE polar wave (0-30°). The biomimetic design based on bamboo offers significant potential for engineering applications in stealth technology under adverse conditions.