Abstract:
This paper presents a graphene-based tunable polarization-insensitive metamaterial absorber (MMA) at terahertz (THz)
frequencies. The absorber consists of top patterned gold (Au) layer followed by single layer of graphene, dielectric spacer,
and Au layer at bottom. The proposed MMA demonstrates multi-band absorption with the characteristics of both broadand
dual-band absorption by optimizing dimensions (parametric analysis). Broad-band absorption reaches over 90% for
the range of 4.57–6.45 THz with the relative absorption bandwidth of 34%, and the absorption peak at 6.86 and 7.20 THz
having 98.9 and 95.2% absorption. The normalized impedance and constitutive electromagnetic parameters of the MMA are
calculated using the Nicolson–Ross–Weir (NRW) method to validate the absorption rate. Furthermore, proposed absorber is
polarization-insensitive upto 90° for transverse electric wave. The tunable characteristic of MMA is achieved by tuning the
Fermi energy of graphene with the application of bias voltage. Accordingly, the proposed multi- and broad-band absorbers
find its potential applications in spectroscopy detection, imaging, and sensing.
