A Single Layer High-Gain Terahertz Reflectarray Antenna for Next Generation Wireless Communication

The design and development of terahertz (THz) reflectarray antenna is presented with a hybrid asteroid–stub–cross unit cell to achieve continuous and complete 360° reflection-phase coverage with minimal amplitude variation of -1.6 dB for an operating frequency of 1 THz. The proposed reflectarray consists of 417 elements arranged with a spacing of 0.5λ, demonstrating significant suppression of -120 dB between the co-polar and cross-polar components. This proposed reflectarray antenna demonstrates a peak gain of 25.3 dBi, a 3-dB beamwidth of 5.5°, a fractional gain bandwidth of 30.8%, a sidelobe level (SLL) of −19.5 dB, and a total radiation efficiency of 88%, validating accurate phase synthesis, high aperture efficiency and minimal phase-quantization error from 1 to 1.5 THz. In addition, the desired phase distribution across the aperture is generated by calculating the phase compensation for each element using MATLAB code. These results are then integrated into the design through a parametric scaling factor α, which is applied to the geometry of the unit cell. A pyramidal horn antenna designed for providing uniform illumination of the 417-element reflectarray, which is built on a low-loss quartz substrate with a gold conductive layer. Owing to its compact aperture, high directivity, and stable broadband behavior. From the results, the proposed design is a strong candidate for 6G THz wireless communication links.