Ground Anisotropy and Extremely Low Frequency (ELF) Transmitting Antennas

The surface impedance concept is used to examine the effect of ground anisotropy on the radiated field and power dissipation of a horizontal ELF transmitting array. The principal result, for a simple homogeneous but anisotropic ground, is that even though the ground skews the antenna pattern, any attempt to reorient the array to steer the pattern peak towards the receiver incurs an increase in power dissipation. In fact, the power dissipation is minimized by steering the pattern peak even further away from the receiver.