Optical and electromagnetic absorption features of hierarchical pampon and cauliflower-like magneto/dielectric composite based absorber for C and X bands application

Hydrothermal and in-situ polymerization methods were used to successfully fabricate a pompon flower-like CoGd_0.5Fe_1.5O₄ (CG) as a magnetic component and a cauliflower-like poly(indole-co-Py) (PP) co-polymer as a dielectric component for microwave absorption. The physico-chemical properties of CG/PP samples were determined via XPS, XRD, FTIR, BET, UV–vis, EDS, and FESEM analysis. VNA and VSM were used to evaluate the dielectric and electromagnetic properties of the CG and PP samples. The results of the absorption capability tests revealed that bi-layer samples outperformed single layer samples in terms of microwave dissipation capability. The thickness and arrangement of each layer in bilayer absorber effectively adjusted via MATLAB simulation. As a consequence, the effective absorption bandwidth in the bilayer absorber has been increased and covers the C and X bands entirely with a thickness of only 2 mm, in which 1 mm of CG composite layer with 1 mm of thickness is placed as an absorbing layer and a PP composite layer with 1 mm of thickness is considered as a matching layer. The hierarchical structure of both components (pompon and cauliflower-like morphology) may increase interfacial polarization, relaxation loss, and consequently attenuation constant of the absorber as well as improve impedance matching characteristics and decrease in density. Synergistic effects between two distinct layers containing magnetic and dielectric components may further increase the absorption feature.