The gain-resistance product of the half-wave dipole

It is shown that the gain-resistance product of a half-wave dipole remains constant, although mutual effects of nearby dipoles, or nearby conducting planes, cause its resistance to vary. Thus the gain, the effective area, and the antenna factor of the dipole vary as well.

[1]  P. S. Carter,et al.  Circuit Relations in Radiating Systems and Applications to Antenna Problems , 1932, Proceedings of the Institute of Radio Engineers.