Calculation of effective permittivity and optimization of absorption property of honeycomb cores with absorbing coatings

This paper focuses on the honeycomb cores with absorbing coatings, the effective permittivity is predicted and the absorption property is optimized. The correctness of effective results is verified by experimental measurement, numerical simulation and theoretical analysis. When honeycomb cores with absorbing coatings are regarded as layered multi-phase materials, the upper and lower bounds of effective permittivity are calculated by the way of multi-step equivalence. In order to exhibit the dispersion effect, the improved strong fluctuation theory is proposed. In the second part of works, the size optimization is executed to improve absorption property. The optimization problem is defined that the area T which is surrounded by the effective reflectivity curve and the boundary line (R₀ = -10 dB) is maximized under the upper bound constraints of reflectivity and volume fraction. The optimal effective reflectivity curve is obtained within the given frequency range.