A comparison of the classical theory and the scattering theory of receiving antennas

The theory of receiving antenna is one of the subjects developed in the early period of radio engineering. We will designate the theory formulated by A.F. Stevenson in 1948 as the classical theory and the theory formulated recently by the present author as the scattering theory of receiving antennas. The two theories we quite different. We will review the classical theory first and point out a useful feature of that theory. An outline of the new theory will then be presented. In the new theory we treat the receiving antenna as a lossy scattering body. Poynting´s theorem is applied to the transmitting/receiving system to derive the equivalent circuit relations. Unlike the classical theory, the power relation of the system is automatically satisfied. One important feature of the new theory shows that the mutual impedances between the transmitting antenna and the receiving antenna are not equal to each other.