What are Fresnel coefficients?
Fresnel reflection coefficients quantify the amplitude of reflected and transmitted signals at boundaries. The ratio of the reflected-to-incident signal amplitudes is the reflection coefficient; the ratio of the transmitted-to-incident signal amplitudes is the transmission coefficient. Reflection coefficients depend on the angle of incidence, the polarization of the incident field, and the velocity contrast. Figure 3 illustrates the variation of the reflection coefficient versus angle of incidence and polarization for a GPR wave incident at the water table where a velocity contrast of 1.6:1 might occur.
