Perfect dual-band metamaterial absorber based on octangle-shaped structure

A novel dual-band, thin and polarization-insensitive metamaterial absorber is proposed, it can realize the perfect absorptivity at 36GHz and 42.1GHz. The perfect absorber has three layers, lossy-FR4 in the middle with copper layers on both sides. The basic geometry of top octangle-shaped resonant copper layer is constructed by the overlapping of three disks. From the surface current distributions of the structure, we can find the strong resonance phenomena happened at 36GHz and 42.1GHz. For the top layer is symmetrical, the absorptivity of the structure almost not change with the polarization angle of the incident wave.