Distortion of transient pulsed fields in propagation above a highly refractive half-space

Both electric and magnetic current sources are considered. The technique is based upon the exact image theory developed by Lindell and Alanen (1984). A computational technique, valid where the refractive index of the medium is large, is accurate over a wide range of frequencies, particularly at grazing incidence. The formulae can be written in terms of the complementary error function of a complex argument. Although closely related to the surface-wave expansion, the formulae derived are valid for all angles and in the far-field reduce to the reflection coefficient method (RCM). The efficiency of this computational technique allows the practical use of frequency domain analysis for the reflection of transient pulses. Example calculations are provided using a Gaussian current pulse, and the validity of the RCM is discussed. Regimes in which significant distortion of a transient pulse occurs are identified