Against the backdrop of the rapid development of electromagnetic stealth technology, the design and optimization of structural absorbing materials with both wave-absorbing and load-bearing functionalities has emerged as a significant research trend in this field. However, this type of material has diverse components and complex structures, making it difficult to characterize its electromagnetic parameters. Moreover, in electromagnetic modeling, it encounters problems such as a large number of mesh divisions and significant multi-scale effects, which results in low computational efficiency and difficult solution.

This study aims to perform an equivalent processing for honeycomb composite materials with dispersion characteristics and anisotropy by introducing an improved S-parameter inversion method. The objective is to efficiently establish an accurate equivalent electromagnetic model while ensuring that the macroscopic scattering characteristics remain unchanged.

Using three-dimensional electromagnetic simulation software CST and a free-space measurement system, the modeling, simulation, and practical testing of the honeycomb structure and its equivalent flat plate were successfully accomplished. By varying the incident angle of the plane wave, the scattering parameters of the honeycomb model were obtained under both normal and oblique incidence conditions. Through an inversion procedure, the equivalent electromagnetic parameters corresponding to each incident condition were sequentially derived and subsequently applied to the equivalent homogeneous flat plate, thereby achieving the equivalency treatment of the honeycomb structure.

The simulated and measured scattering parameters of the honeycomb structure, both before and after equivalence, were compared and revealed a high degree of agreement. This result strongly validates the accuracy and feasibility of the proposed equivalent method.

This paper adopts the improved S-parameter inversion method, and for the honeycomb absorbing structure under different plane wave incidence angles, completes the extraction of its equivalent electromagnetic parameters and the construction of the equivalent model. The consistency of the equivalent results validates the accuracy and feasibility of the method and provides a reliable solution for the efficient electromagnetic modeling of honeycomb absorbing structures.