Ultralow Thickness-Bandwidth Ratio Magnetic Absorber With Printed FSS for S&C Bands

The thickness-bandwidth ratio (T-BR,
d
:
λ
_max
−
λ
_min
) is an important evaluation factor for designing a thin broadband absorber. In this letter, an ultralow T-BR magnetic absorber using frequency selective surfaces (FSS) is designed aiming at the S&C bands. We add a superstrate and a substrate both made of magnetic material and printed the FSS pattern with resistive ink. By optimizing the circuit parameters of the lumped elements and the size of the unit cell of the FSS pattern, the proposed absorber provides 120% bandwidth of −10 dB reflectivity level in the S&C bands (2 GHz–8 GHz), whereas its thickness is only 0.033
λ_L
(5 mm). The T-BR of the proposed absorber is 0.044, which is much lower than that of most absorbers reported works. In addition, the proposed absorber also has the characteristics of radar cross section reduction at different angles. The fabricated absorber proves that the measured results match well with the simulation results.