Design of a terahertz dual-channel modulator based on metamaterials

In this paper, we propose a terahertz dual-channel modulator by combining a high electron mobility transistor (HEMT) with a metamaterials structure, in which the HEMT is embedded in the opening of the structure metamaterial. The modulator consists of a metamaterial structure, silicon carbide (SiC), HEMT active device, and feeder. The concentration of the two-dimensional electron gas (2DEG) in the HEMT can be controlled by gate voltages, and the change of the concentration can realize the modulation of the intensity and phase of the terahertz wave. The simulation results indicate that when a single channel works, the modulation depth is 90.7% at 0.22 THz and 94.0% at 0.34 THz. When both channels work, the modulation depth is 88.9% at 0.22 THz and 93.3% at 0.34 THz. The terahertz modulator designed in this paper can work in two frequency bands and can be controlled independently, which efficiently uses the spectrum resources and has broad application prospects in the field of terahertz communication.