Th£ GROUND-WAVE ATTENUATION FUNCTION FOR PROPAGATION OVER A HIGHLY INDUCTIVE SURFACE

Propagation of an electromagnetic ground wave over a plane surface in which the argument of the surface impedance is greater than n/4 but ; A less than TT/2 is considered in some detail. The numerical distance, p, over such a surface is characterized by 0 f arg p £ n/2 . The ground wave behaves in a rather unusual manner, and this is attributed to the interaction of phasors representing a trapped wave and a Norton surface wave. Approximate expressions are derived which determine the magnitude of the ground wave attenuation function at its maxima and minima as well as the phase at these points and the numerical distances where these maxima and minima occur. A method is also given for estimating the asymptotic phase for large |.pj which wa6 previously not possible. Finally, detailed curves are presented which show the amplitude and phase of the ground wave attenuation function versus p. These curves should prove useful to practicing radio engineers attempting to make calculations for surface wave propagation over corrugated, stratified or rough surfaces. THE GROUND-WAVE ATTENUATION FUNCTION FOR PROPAGATION OVER A HIGHLY INDUCTIVE SURFACE R. J. King and G. A, Schlak