Terahertz single dual multi-band metamaterial absorber

Abstract

In this study, a new multifunctional terahertz (THz) metamaterial absorber (MMA) has been presented which is controlled by the thickness of the substrate used. The proposed structure consists of copper as the ground plane and polyimide dielectric layer is placed in between the ground panel and the top radiating patch. The resonant frequency and number of resonating modes of the proposed absorber can be changed by varying the thickness of the substrate from 10 to 100 $\mu$m for the same planar structure. Depending on the thickness of the substrate, this MMA gives a narrow (10 $\mu$m), double (20 $\mu$m), triple (30 $\mu$m), quad (50 $\mu$m) and hexa (100 $\mu$m) number of resonating modes. In order to analyse the physical mechanism of the proposed absorber, we took 10, 20 and 30 $\mu$m-based MMA and their electric and magnetic field distributions are demonstrated. We compared the resonant frequency ranges and the number of bands with the previously reported papers. The polarisation and angle insensitivity of the design have been validated by numerical simulation up to 90$^\circ$ of oblique incidence. The effects of variation in geometrical parameters and sensing habits have been studied in the narrow band (10 $\mu$m) MMA structure. The designed multifunctional absorber has the advantage of using the same MMA to produce multiple (narrow, double, triple, quad and hexa) band absorbers.