Design of a Directional Borehole Radar System

Borehole radar plays a pivotal role in the realm of geophysical exploration as it possesses a larger detection depth than traditional ground-penetrating radar (GPR). This paper presents a cutting-edge borehole radar system for the detection and direction determination of subterranean targets. This radar system is composed of an omnidirectional dipole transmitting antenna and a six-dipole-element receiving antenna array. Operating at a frequency of 100 MHz, the antennas are optimized to achieve a long-range detection. Besides, a modified Multiple Signal Classification (MUSIC) algorithm is proposed for estimation of the Direction of Arrival (DOA) from reflection signals recorded by the six-element antenna array. The efficacy of the designed radar system and the DOA estimation algorithm are demonstrated through numerical simulations, showcasing enhancements in the antenna’s radiation efficiency and bandwidth. The average relative error of the target’s azimuth orientation estimation results has been reduced to as low as 0.2%.