Dual-Frequency Polarized Reconfigurable Terahertz Antenna Based on Graphene Metasurface and TOPAS

A hybrid dual-frequency polarized reconfigurable terahertz antenna is designed and studied. Graphene and TOPAS are employed as the polarization conversion metasurface and dielectric substrate, respectively, enabling tunable polarization conversion and circular polarization. TOPAS is a good substrate material for broadband THz components due to its low absorption. By adjusting the chemical potential of graphene between 0 eV and 0.5 eV, the polarization state in the band of 1 THz (0.76–1.02 THz) and 2.5 THz (2.43–2.6 THz) can be reconstructed. Thanks to the multilayer graphene structure and low absorption TOPAS, the graphene metasurface exhibits a broad bandwidth of 0.26 and 0.17 THz, respectively, in the band of 1 THz and 2.5 THz. The working state of the circularly polarized antenna and linearly polarized antenna can be switched in the bands around 1 THz (0.7–0.75 THz, 0.96–1.04 THz) and 2.5 THz (2.42–2.52 THz), respectively, without changing the physical geometry. Moreover, the graphene antenna, metasurface, and hybrid structure are tested, respectively, to verify that the components do not interfere with each other in performance. The hybrid antenna shows great potential in tunable terahertz devices and related applications.

Study of The Spectral Response of A Terahertz Antenna Detector When The Surrounding Dielectric Changes

In this paper, the surface wave theory is used to study the spectral response of a terahertz antenna detector when the surrounding dielectric material is changed. As simulation shows, surrounding dielectrics affect the velocity of the current pulse propagation on electrodes. The propagation spectrum of the bow-tie and the dipole antenna on the LT-GaAs substrate is simulated through the FDTD method using the CST software. The current pulse generated in the antenna gap is also calculated with the Drude model. It is found that the type and the thickness of surrounding dielectrics affect the spectral responses of detector antennas as far as the peaks of the corresponding spectra shift down to one terahertz.