Graphene-based frequency reconfigurable slot antenna for terahertz applications

This research presents the design of a multi-band frequency reconfigurable slot antenna (FRSA) that utilizes graphene in the terahertz (THz) regime. The proposed FRSA supports independent switching across twenty-nine operating bands: 0.518, 0.532, 0.56, 0.59, 0.636, 0.648, 0.66, 0.682, 0.724, 0.752, 0.758, 0.84, 0.938, 0.906, 1.166, 1.252, 1.256, 1.26, 1.304, 1.324, 1.336, 1.344, 1.532, 1.648, 1.70, 1.784, 1.95, 2.01, and 2.064 THz. The design features a rectangular patch with both vertical and longitudinal slots and incorporates seven graphene switches (labeled d1–d7) placed along these slots. These switches enable reconfigurability by controlling the surface conductivity of the graphene. The tunable properties of graphene present significant potential for developing smaller, reconfigurable antennas in THz wireless systems. The proposed FRSA features a compact design with dimensions of 268 µm x 240 µm x 10 µm, or 0.46 λ₀ × 0.41 λ₀ × 0.017 λ₀, where λ₀ represents the wavelength corresponding to the lowest operating frequency of 0.518 THz in free space . The patch structure is mounted on a 10 μm thick substrate made of Rogers RO3003 (with ε r = 3 and tanδ = 0.001). The surface conductivity of graphene sheets is adjustable by applying a bias voltage , which influences the chemical potential of the graphene. The FRSA operates in ten states (S1–S10), determined by the ON and OFF positions of the graphene sheets. An analysis of the antenna performance was conducted, examining the reflection coefficient , and gain at various chemical potentials. This switching capability enables secondary users to access unused frequency bands, making the antenna suitable for cognitive radio applications. Furthermore, this technology can be applied in medical settings, as the antenna can assist in identifying skin conditions and cancerous tissues. By switching between different frequencies, it can improve imaging quality and capture various types of data about the body being examined.