Scattered and absorbed powers in receiving antennas

Several articles have recently appeared in the Magazine concerning the question of how much power was scattered and absorbed by a receiving antenna and, in particular, whether an antenna can absorb all of the power incident upon it. By defining a suitable aperture efficiency for the receiving case, it was shown that a dipole array without a ground plane can at best absorb half of the incident power, while an array over a ground plane can absorb all of the incident power.