Thickness optimization of a triple-layered microwave absorber combining magnetic and dielectric particles

The objective of this research is to optimize the thickness of a triple-layer microwave absorber using a genetic algorithm (GA). The materials employed in this study consist of a combination of magnetic and dielectric materials, along treated dielectric material, to create a triple-layer absorber. S-parameters (S₁₁ and S₂₁) were obtained from measurements of these materials with a thickness of 2 mm using a Vector Network Analyzer (VNA). Input parameters, including relative complex permeability and relative complex permittivity, were derived by converting the S-parameters using a conversion program based on the Nicolson-Ross-Weir (NRW) method. The thickness of each sample was optimized using GA to achieve a high reflection loss value (RL_min⁡ ) by entering the relative complex permeability and relative complex permittivity values. The results indicate that the optimization of the thickness of the reflection loss equation for the triple-layer absorber from six triple-layer absorber results in high RL_min (-61.76 dB) at optimum thickness of d₁ = 2.17 mm, d₂ = 1.6 mm, and d₃ = 3.76 mm at a frequency of 10.76 GHz, with a bandwidth of 0.58 GHz. Optimizing the thickness and the number of layers is crucial in the design of triple-layer radar absorbing materials (RAM) and can produce high values of RL_min .