Effect of frequency-dependent soil parameters on reflection coefficients

The degree with electromagnetic pulse (EMP) energy is predicted above a reflecting plane is strongly dependent on the nature of the plane. The reflection of electromagnetic energy from a surface can be accurately described mathematically, and equations which predict these fields are common knowledge to the EMP community. Although this is the case, some predictive analysis uses models for the Earth's surface which are independent of frequency and considers only an average soil moisture content. This report describes the varieties of electrical properties with frequency and moisture content. It applies these variations to a reflected EMP and assesses the energy difference between models which use parameters independent of frequency and those which use varying parameters. Finally, it discusses the variation of soil properties with depth and predicts the magnitude of energy, above the ground, which may result from this variation.