Diakoptic theory for multielement antennas

A theory is presented for the analysis of multielement antennas consisting of interconnected, conductive structural elements of electrically small dimensions. The theory is based on the retarded electromagnetic potentials which make possible a diakoptic approach to the problem. The antenna is broken up into its individual structural elements; each element is assumed to be excited by currents which are impressed at its terminals, that is, junctions with adjacent elements (current coupling) and by the electric fields of the currents and charges on all the other elements (field coupling). The excitations are both treated independently. Each impressed current produces a 'dominant' current distribution, a characteristic of the element, which is readily computed. Current coupling is formulated through 'intrinsic' impedance matrices which relate the scalar potentials at the terminals of an element, caused by its dominant current distributions, to the impressed currents of the element. A simple example is included to demonstrate that the diakoptic theory yields very good results, even when greatly simplified assumptions are made.