Abstractive and selective properties of radio antenna circuits

13. The maximum power which an antenna can abstract from sustained waves and deliver to a detector. To make the delivery of power from sustained waves to the detector associated with a given antenna a maximum, the equivalent resistance of the detector, R
d
, should be made equal to the sum of the radiation resistance, R
r
, plus the wasteful resistance R
w
, of the antenna. Let us assume that the detector is so proportioned, and that the ratio of the resistance is as expressed in equations (1) and (2).