Leaf vein micronetwork engineering enhanced energy conversion strategy for C‐band ultralight yet tunable microwave absorption

Abstract Lightweight materials with wide absorption capabilities, particularly in the C‐band, have remained a challenge thus far. Recent research has indicated that effective absorption networks built by microfiber polarization loss can be a significant factor in increasing the effective absorption bandwidth (EAB). In this study, leaf vein‐like carbon (LVC) was synthesized using an in situ blowing strategy. Taking inspiration from photosynthesis energy conversion mechanisms, a leaf veins‐like hierarchical structure was created to establish an effective impedance‐matching network and generate a high‐density polarization region through leaf vein microfibers. This enhanced polarization relaxation effectively broadens the EAB of the LVC. At a low filling ratio of 6.3 wt%, the EAB of the LVC covers 80% of the C‐band, as well as 100% of the X‐band and Ku‐band. Achieving such a wide EAB in the C‐band, especially in the multi‐band context, relies on impedance matching and optimized polarization relaxation. This work demonstrates the crucial role of leaf vein micronetwork engineering in enhancing the C‐band absorption properties of carbon‐based materials, thus providing a viable reference for the development of lightweight, broadband, and highly absorptive materials for electromagnetic applications.