On measuring electromagnetic surface impedance - Discussions with Professor James R. Wait

Electromagnetic (EM) surface impedance, defined as the ratio of the horizon tal electric field to the horizontal magnetic field perpendicular to the pl ane of incidence, has been used in geophysics since the early 1950s for sub surface earth mapping. Traditionally, the electric field component has been measured using a staked voltage probe. In 1989, Wu and Thiel suggested tha t an insulated wire dipole without the stakes was a more reliable measureme nt technique. Wait responded to this paper and the discussion continued unt il Wait's last comments were published in 1999. In this paper, the final ar guments are summarized. The major conclusion reached is that either techniq ue can be used provided caution is exercised, particularly at higher freque ncies.