A reconfigurable multi-band, multi-bias THz absorber

Abstract

A configurable terahertz (THz) graphene-based metamaterial absorber is designed in this paper. Taking advantage of dual bias graphene ribbons and disks with a golden plate, the reconfigurable absorber achieves absorption over 90% in three frequency bands include 0.8–2.2 THz, 5.5–6.5 THz and 7.5–8.5 THz. The chemical potentials of graphene patterns are optimized using a genetic algorithm. As the chemical potentials vary in the range of 0-0.6 eV, the device adds absorption bands while maintaining the previous absorption in lower frequencies. The whole device includes dielectrics, golden plate, and dual bias graphene patterns are modeled via the circuit model approach to calculate referred input impedance. This impedance is investigated regarding chemical potential effects on perfect absorption while other physical parameters such as ribbons widths and disks radiuses are fixed. Finally, the obtained suggestions of the algorithm are exploited to simulate the device with both full-wave numerical simulations as the finite element method (CST) and circuit model approach (MATLAB). According to simulation results, numerical simulation verifies validity and accuracy of circuit modeling to describe proposed device behavior. Compared to previous works, the proposed device as a reconfigurable THz absorber can overcome the limitation of traditional absorbers due to the capability of an add frequency band in absorption response while exhibits great potentials in many practical applications.