GA based optimized graphene antenna design for detection of explosives and drugs using THz spectroscopy

Explosives and contraband drug detection have been a persistent problem for the last few decades and have emerged as one of the numerous crucial issues in public safety and counter-terrorism. Due to the risks to human cells and the inability to detect all forms of explosive materials, traditional detection techniques like x-rays and metal detectors are inadequate to combat these issues. Terahertz imaging and spectroscopy have solved the aforementioned problems because nonionizing radiation is harmless to humans and can also find objects hidden under non-metals. The proposed research work designed multi-layered dual-band graphene antennas for the THz spectroscopy applications utilising uni-layer triple substrate method, i.e., three substrates at the same height w.r.t. ground. The genetic algorithm optimizes a design antenna with 5.59 & 7.71 THz resonant frequencies, lower used to detect TNT explosives and upper ones used to detect melatonin drugs. The optimized antenna has radiation efficiency (%) values of 79.51 & 77.51, S11 parameters of −48.22 & −43.95, VSWR of 1.007 & 1.012 and bandwidths of 145.9 & 148.4 GHz at both resonating frequencies. In terms of antenna's gain (dB) and directivity (dBi), the optimized antennas show better performance with values of 4.65 & 2.97 and 5.87 & 4.07, respectively. The overall results demonstrated that, while being smaller, the optimized antenna outperforms the conventional one.