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

The purpose of this study is to optimize the thickness of the double-layered microwave absorber for obtaining the highest absorption. The graphenic-based carbon compounds and Fe3O4 magnetic particles were combined to fabricate the double-layered absorber. The thickness was optimized by employing a genetic algorithm (GA) to obtain high reflection loss values. These samples at a thickness of 2 mm were measured for reflection loss (RL) with a Vector Network Analyzer (VNA). Input variables, such as relatively complex permeability and relatively complex permittivity, were obtained using a conversion program that uses Nicolson-Ross-Weir (NRW) method from VNA S-parameter values (S11 and S21) data. By entering the permeability and permittivity of the complex relative to GA, the thickness can be optimized to produce high value. Optimization of the double-layer thickness of 12 absorbers produces the optimum thickness of 1= 5.99 mm and 2 = 0.87 mm among the materials combination, which results in a high L (-44.69 dB). This optimization is very important for designing double-layer radar absorbing material (RAM) which results in high L values.