A Compact Low Frequency Vivaldi Antenna for Ground Penetrating Radar

One of the most important parts in ground penetrating radar (GPR) system is the antenna. To transmit the waves to deep depths, the operating frequency should be decreased as possible. A compact Vivaldi antenna is proposed with operating frequency of 0.4 GHz and dimensions of (0.26λ_o×0.21λ_o×0.002λ_o), where λ_o is the free-space wavelength at the operating frequency. To increase the gain of the Vivaldi antenna, the length of antenna should be increased. The conventional Vivaldi antenna length should be greater than λ_o. In order to improve the gain of the Vivaldi antenna while maintaining a compact size, a triple slot line structure is proposed. The Vivaldi antenna is etched on a thin economic substrate (FR4) with permittivity of ε_r=4.4 and thickness of h=1.6 mm. ith permittivity of ε_r=4.4 and thickness of h=1.6 mm. ith permittivity of ε_r=4.4 and thickness of h=1.6 mm. ith permittivity of ε_r=4.4 and thickness of h=1.6 mm.