A new approach to designing a multiband antenna using photonic crystals and load graphene for terahertz application

The primary concern addressed in this article is the inherent difficulty in creating antennas capable of effectively operating across a range of frequency bands within the terahertz (THz) spectrum. Conventional antenna designs often fall short in terms of delivering the required bandwidth and power for such applications. To mitigate this problem, we present a technique that uses photonic crystals integrated into the antenna design to generate photonic band gaps (PBG) with the graphene loaded in the THz band. So, the purpose was to find the optimal multiband antenna that can function across 1.13 and 0.65 THz. Simulations were conducted for rectangular patch antennas using different types of substrates, which included homogeneous, periodic, and aperiodic photonic crystal substrates, and by using a graphene load, simulations were carried out. Multiple sets of air holes (rectangular and cylindrical) were punched into the polyimide substrate of each modified photonic crystal substrate, and the load graphene was placed in the patch. The anticipated multiband antenna design has successfully achieved impressive performance metrics, including a minimal reflection coefficient of -36.8 dB and -41.812 dB, a substantial bandwidth of 25 GHz, and 110 GHz at 0.65 THz and 1.13 THz, respectively. Additionally, the design boasts a gain of 6.44 dBi, 9.45 dBi, and a remarkable radiation efficiency of 75.12% and 80.03%, respectively, with a VSWR < 2 at the resonating frequencies. The distinctive attributes of PBG, combined with the multiband capabilities of the antenna, position it as a highly promising option for terahertz imaging systems like those used for detecting concealed objects in settings such as airports. Furthermore, its potential extends to biomedical imaging, where it could be utilized to identify tissue irregularities with improved clarity and contrast.