Lateral waves in ground penetrating radar applications

This paper discusses about the lateral wave phenomenon encountered when an antenna or scatter is close to dielectric interface. Although such wave mechanism has been known for its existence in theory and observed in measured data. Most GPR operators are not familiar with the behavior and effects of lateral waves related to ground GPR surveys. The one way propagation loss (in power) of lateral waves is independent of soils and follows behavior of 1/ ρ⁴ (ρ: lateral distance to the source). This is greater loss compared to air and ground waves which are spherical waves. However, over a large lateral distance, the amplitude of lateral waves near ground surface eventually exceeds that of ground wave. The latter suffers from exponential decay in lossy soils. This phenomenon makes lateral waves interesting for forward-looking GPR but also potentially introduce surface clutter in GPR survey data. This paper will discuss properties of lateral waves via 3D simulations. Possible applications of lateral waves in forward-looking GPR configuration in homogeneous and layered ground will also be discussed.