A Broadband Wide-Angle Metamaterial Absorber

In this paper, a broadband, wide-angle, polarization-independent metamaterial absorber is presented, which consists of a horizontal frequency-selective surface and an array of vertical copper columns connected by metal strips. The simulated results indicate that this absorber could operate between 2.23~5.41 GHz (fractional bandwidth of 83.25%) with a reflectivity less than −10dB at normal incidence, while its thickness is only 13mm ($0.096\lambda _{\mathrm{L}}$ at the lowest operating frequency). Besides, a wide-angle absorption performance is also illustrated when its periodic size is 21mm (>0.15$\lambda_{\mathrm{L}}$). For an incident angle no more than 50°, the presented absorber maintains its absorption with a reflectivity less than −10dB for both TE and TM waves at 2.35~5.37 GHz and 2.57~5.86 GHz, respectively.