Investigating the Performance of Bi-Static GPR Antennas for Near-Surface Object Detection

Abstract

Antennas are an important component in ground penetrating radar (GPR) systems. Although there has been much research reported on the design of individual antennas, there is less research reported on the design of the geometry of bi-static antennas. This paper considers the effects of key parameters in the setup of a GPR head consisting of a bi-static bow-tie pair to show the effect of these parameters on the GPR performance. The parameters investigated are the antenna separation, antenna height above the soil, and antenna input impedance. The investigation of the parameters was performed by simulation and measurements. It was found when the bi-static antennas were separated by 7 cm to 9 cm and were operated close to the soil (2 cm to 4 cm), the reflected signal from a near-surface object is relatively unaffected by height variation and object depth. An antenna input impedance of 250 Ω was chosen to feed the antennas to reduce the late-time ringing. Using these results, a new GPR system was designed and then evaluated at a test site near Benkovac, Croatia.

Combined Migrations and Time-Depth Conversions in GPR Prospecting: Application to Reinforced Concrete

“…The two results of Figure 5 have been combined in Figure 6, with a linear transition between the left-hand and the right-hand images imposed in the abscissa range 40-54 cm. The data were also cut at the depth level 9.4 ns, beyond which, as it is quite clear from Figure 6, we essentially see the amplified ringing [21] of the antennas. The joining was implemented with a homemade code written in MATLAB environment.…”

Reducing the Induction Footprint of Ultra-Wideband Antennas for Ground-Penetrating Radar in Dual-Modality Detectors

“…The transformer baluns are smaller, have a lower reflection coefficient, and have better reproducibility between devices, but their output impedance is lower than that of the tapered baluns, which were designed to have a 200 Ω output impedance. In previous work it has been found [22], [23] that feed impedance at the antenna terminals changes the time-domain signal of the radiated pulse. The higher output impedance from the tapered baluns is preferred in this experiment to reduce the ringing in the time-domain.…”

Ballistic Ground Penetrating Radar Equipment for Blast-Exposed Security Applications

“…As previously discussed, the antenna height above the ground is a critical factor, affecting both the design of the GPR platform and the quality of the collected data. It is clear that a stand-off radar system might represent a reasonable choice when surveying a hazardous area, but the impact of elevating the antennas on the reflected signal strength must be evaluated [45,46]. Figure 4 describes the penetration loss experienced by elevating the GPR sensor above the ground surface.…”