Optimized Logarithmic Spiral Antenna for GPR System to Detect Landmines and Explosives

This article focuses on the design of a Logarithmic Spiral Antenna (LSA) and the analysis of its performance for a GPR system used to detect landmines and explosive devices, operating within a frequency range of 2 GHz to 5 GHz. The parameters of the LSA have been optimized through a parametric sweep utility in CST Studio to accommodate aforementioned wide frequency band. The two types of baluns, tapered balun, and Marchand balun, have been used to feed the LSA, and their comparative analysis suggests that with tapered balun, operating frequency remains intact. Additionally, the antenna performance has been investigated on two substrate materials, FR-4 and Rogers RT Duroid 5870, yielding better result on latter as substrate. In conclusion, the logarithmic spiral antenna integrated with a tapered balun on Rogers RT Duroid 5870 substrate exhibits excellent radiation characteristics, including appropriate 3dB axial ratio, broad VSWR bandwidth, high efficiency, and consistent gain across the entire operational bandwidth.