Miniaturized ultra-wideband microstrip graphene patch antenna for THz applications

An investigation of five different patch-shaped novel graphene-based terahertz (THz) antennas has been conducted to propose a solution to the inherent narrow-bandwidth problem of microstrip patch antennas. The investigated shapes are hetero-hexagonal, homo-hexagonal, pentagonal, square, and circular. The achieved −10 dB bandwidth for the hetero-hexagonal antenna is 20.35 THz, 19.77 THz for the pentagonal and square antenna, 19.70 THz for the homo-hexagonal antenna, and 19.37 THz for the circular antenna. The antenna demonstrates a remarkable operational frequency range of 9.37–30 THz with an excellent S11 of -41.44 dB. The overall fractional bandwidth of the antenna is 104.76% with a bandwidth ratio of 3.2:1. All the proposed antennas possess high radiation efficiency with a value of more than 84% and a very high gain of more than 15.40 dBi. In addition, these antennas are very compact, with a dimension of 55 × 55 μm². The antenna performance has been further evaluated for Teflon (ε_r = 2.1), Roger RO 3003 (ε_r = 3), and Silicon Nitride (ε_r = 1) substrates, and it has found that the silicon–nitride (Si₃N₄) substrate works well with the proposed design. Using the CST Microwave Studio, the antenna’s overall performance is assessed. The proposed antenna’s exceptional gain, wide bandwidth, and efficiency make them perfect for high-speed wireless communication and future networks, including 5G/beyond 5G and 6G. These antennas are designed to operate within the THz range, endowing them with significant value in applications including medical imaging, material inspection, and security screening.