Permittivity qualification, prediction, and regulation of absorption composites for high-efficiency microwave compatibility and management

Electromagnetic waves management in electronic equipment is an important premise to ensure the efficient and stable operation of components. In this work, aimed at the 2–18 GHz frequency spectrum, a novel theoretical framework for achieving effective absorption (reflection loss < -10 dB) is established and applied to deduce the ideal ranges of permittivity, input impedance, and attenuation constant for arbitrary thicknesses. Guided by the ideal electromagnetic parameter qualification model, multiphase composites with complex dielectric characteristics are constructed, which are composed of 3D graphene skeleton, SiC interface, and SiBCN matrix, to verify the regulation of the electromagnetic properties. Based on electric field simulation, the permittivity, microstructure, and composition of the composites are systematically predicted, regulated, and optimized. Therefore, the enhanced absorption performance can reach a minimum reflection loss of -39.4 dB and a maximum effective absorption bandwidth of 2.96 GHz. Furthermore, a new empirical permittivity mixing model which can suit the composites is preliminarily developed, demonstrating excellent permittivity prediction accuracy. This work provides a paradigm shift in microwave compatibility and management in electronic components through coupled theoretical-experimental advancement.