Design, Characterization, and Optimization of a Multilayer U-type Hexaferrite-Based Broadband Microwave Absorber

Design and development of broadband thin multilayer microwave-absorbing materials (MAMs) are described in this paper. Design and analysis of single-, two-, three-, and four-layered MAM are covered in detail. CoCr-based U-type hexaferrite MAMs Ba
₄
(Co
_1-3x
Cr
_x
)
₂
Fe
₃₆
O
₆₀
for various values of x (x = 0.05, 0.1, 0.2, and 0.25) have been used as base materials. Thickness and material layers have been optimized using genetic algorithm (GA). Reflection loss (R
_L
) of -50 dB has been obtained using single-layered MAM at 2.21 mm thickness with effective bandwidth of 1.5 GHz. R
_L
value has been optimized in two-, three-, and four-layered MAM and R
_L
of -80.94 dB has been obtained using four-layered MAM at 1.801 mm thickness with effective bandwidth of 3.948 GHz. MAMs have been applied on an artillery shell and using electromagnetic (EM) simulation software radar cross-section (RCS) reduction simulation has been carried out for single- and multilayered MAM. RCS reduction of 9.14 dB has been obtained using single-layered MAM and a reduction of 19.86 dB has been obtained for four-layered MAM at 10 GHz. RCS reduction simulations have been carried out in entire X band and a maximum RCS reduction of 29.76 dB has been obtained at 9.5 GHz at 0° aspect angle.