A comparison of three techniques for evaluating the vector potential of a vertical current element radiating over the lossy half-space

Three techniques for evaluating the magnetic vector potential of a vertical current element radiating in air over a lossy half-space are compared. These techniques are the Sommerfeld integration, the reflection coefficient method (RCM), and the high contrast approximation (HCA). Both the RCM and the HCA avoid the need for computing the Sommerfeld integral. The HCA yields acceptable results when the significant distance of the problem (the distance between the image and the field points) is extremely small. The RCM fails in this situation. It is concluded that the RCM and HCA complement each other over a relatively wide range of parameters of practical interest.