Power Aspects of the Equivalent Circuit of an Antenna

The Norton equivalent circuit of a receiving antenna consists of a current generator feeding two admittances in parallel, Y
_a
and Y
_L
. Admittance Y
_L
represents the load, and the power dissipated in Y
_L
, evaluated by "circuit" methods, correctly represents the actual electromagnetic power delivered to the load. The symbol Y
_a
represents the input admittance of the antenna radiating in its transmitting mode. Whether the power dissipated in Y
_a
, again evaluated by circuit methods, is equal to the power scattered by the antenna has been a matter of controversy for quite a few years. The present note seeks to review that recurring problem.