Design of a broadband ultra-thin metamaterial absorber with G-type bent structure

A broadband ultra-thin metamaterial absorber (MA) with a multilayer structure is proposed. The G-type metal layer (GTML) and the square ring metal layer (SRML) are attached to the upper and lower surfaces of the dielectric substrate. Its bandwidth is determined by the high frequency resonant point f_HO and low frequency resonant point f_LO generated by GTML and SRML. The MA with unit size of 19 mm × 19 mm × 8.6 mm was simulated, manufactured and measured. The results show that the bandwidth of the structure can cover 2.89–8.06 GHz, and the relative bandwidth is 94.43%. Compared with other structures, the total thickness of the element is only 0.083λ_L, where λ_L is the wavelength at 2.89 GHz.