Polarimetric antenna for ground penetrating radar based on the resistive-vee dipole

Abstract

A broadband antenna system has been developed to use polarization diversity for ground penetrating radar (GPR) applications. The antenna system uses four, crossed, resistive-vee dipole (RVD) antennas operating bistaticly to measure the transmission and reception of multiple polarizations. The RVD was selected because it has low self clutter, low radar cross section and wideband performance. The RVD is linearly polarized, but other polarizations can be synthesized through the use of two orthogonal RVDs to transmit or receive orthogonal field components. The antenna system is able to distinguish rotationally symmetric and linear targets with its ability to transmit right-hand circularly polarized (RHCP) fields and receive both left-hand circularly polarized (LHCP) and RHCP scattered fields. A target’s type can be identified by comparing the relative amplitudes of the received LHCP fields and RHCP fields. For example, the polarimetric antenna will be able to identify linear targets such as wires or pipes because linear targets scatter LHCP and RHCP fields in equal amounts. The configuration of the RVDs was optimized through simulation to achieve good circular polarization at close range and low coupling between the RVDs. Further simulations were performed which demonstrate that the polarimetric antenna provides sufficient information to identify linear targets from nonlinear ones, even at different target orientations. The polarimetric antenna was constructed and has been shown to also correctly detect and identify linear targets. Additional experiments revealed that the polarimetric antenna is effective for ground penetrating radar applications.