On the Direct Computation of the Time-Domain Plane-Wave Reflection Coefficients

This communication compares different approximate techniques to calculate the transient reflection coefficient for TE and TM plane waves from a lossy half space in terms of accuracy, computational costs and area of validity. By varying angles of incidence and constitutive parameters of the half spaces, it is shown that approximate equations can efficiently and accurately calculate the reflection coefficients in the time domain, if the right equation and enough terms in the approximate series are chosen. To confirm these conclusions, it is considered, as a practical example, short pulses reflected by an operational Ground-Probing Radar from different half spaces.