On the equivalent circuit of a receiving antenna

The equivalent circuit of a receiving antenna consists of a current generator and two admittances: one for the load, and one for the antenna. The short-circuit current, I/sub g/ - receiving property - may be expressed in terms of the transmitting properties of the antenna. The article gives a derivation for the value of I/sub g/. It is assumed, to simplify matters, that the antenna is located in free space, and that its feeding line is a monomode waveguide (a coaxial cable, for example). The extension to multimode lines, or to spatial regions containing linear media (possibly anisotropic, and/or non-reciprocal) is fairly straightforward.