An general formalism for Green's function of induction current on antenna

This paper generalises the familiar concept of system function from the time domain (one dimension) to the spatial domain (three dimensions) for the analysis and design of arbitrary electromagnetic system, including radiating structure. The key concept in the formalism is the current Green's function which can be considered an exact transfer function. We provide a conceptual view framed in terms of one mode which is excitation of a given antenna element by an externally applied field. It is shown that the current Green's function can be obtained in terms of a 2D tensor that depends on the local geometry of the general antenna surface.