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

Abstract

Abstract 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 R L min 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 R L min value. Optimization of the double-layer thickness of 12 absorbers produces the optimum thickness of d 1 = 5.99 mm and d 2 = 0.87 mm among the materials combination, which results in a high R L min (−44.69 dB). This optimization is very important for designing double-layer radar absorbing material (RAM) which results in high R L min values.