A comparative numerical study of several techniques for modeling a horizontal wire antenna over a lossy half-space

The electric-field integral equation for the current on a thin, horizontal wire antenna radiating above a lossy half-space is solved by the method of moments, with the effect of interface included via the Sommerfeld integrals, the well-known reflection-coefficient approximation and the high-contrast approximation. A modified implementation of the reflection-coefficient approximation is suggested, which makes this technique reasonably accurate for antennas near the interface. A comparison is made between the methods for several cases of practical interest. The high-contrast approximation is shown to be superior to the reflection-coefficient approximation.