Design and Optimization of Multilayered Microwave Absorber Structures for X-Band Frequencies: Application on Composite Materials Comprising Ceramic, Polyaniline/Magnetite, and Carbon Nanotubes

The characteristics of multilayered microwave absorbing materials are very efficient compared with those of single layer. In this article, a hybrid optimization algorithm (genetic algorithm + pattern search) combined with transmission line matrix method has been presented. The selection of parameters, including the arrangement of layers, thickness of layers, absorption index, and shielding efficiency, forms the foundation of this process. The optimization algorithm was applied to two new multilayered structures. The first structure consists of conductive layers (CLs) of carbon nanotube (CNT) with ceramic layers of zirconium dioxide $\left({\mathrm{ZrO}}_2\right)$. The second structure includes CLs of CNT with layers based on magnetite polyaniline nanomaterial (PANI_${\mathrm{Fe}}_3{O}_4$). Performances of both structures were evaluated in the X-band frequency range. Simulation results showed that both designs have higher absorption index picks (> 90%) and, low $S_{11}$ magnitude value with low layer thickness. This approach offers a solid foundation for future experimental trials in the development of efficient microwave absorbing and shielding structures with tunable electromagnetic performances suitable for X-band applications.