A terahertz dual-band metamaterial perfect absorber based on metal-dielectric-metal multi-layer columns

In this paper, a new model of multi-layer metamaterial perfect absorber (MPA) in the terahertz region has been introduced. This model is similar to the classic absorber model, ie the three traditional layers of metal-dielectric-metal. The difference is that the middle layer has changed in height and consists of 3 separate layers with the same material. Therefore, the middle layer of the proposed structure is metamaterial. Numerical results of the simulation show that the absorption rate of the perfect absorber at 6.86 THz is 99.99%. Also, by changing the width of the two middle layer columns w, a dual-band perfect absorber with an average absorption rate of 97.18% is obtained at frequencies of 4.24 THz and 6.86 THz. A significant advantage of this paper over other works is that this absorber is adjustable, in addition to obtaining a nearly perfect dual-band absorber with a narrow-band peak by adjusting the parameters and also a nearly broad-band absorber can also be obtained by changing the parameters without re-manufacturing the structure. We believe that the proposed absorber has potential in filtering, detection and imaging.