Theory of loaded scatterers

A general formulation is given for the problem of electromagnetic scattering by an object having N terminal pairs (or ports) to which N loads or an N-port network is connected. The theory is applicable to back scattering and bistatic scattering, reciprocal and nonreciprocal media, near-field and far-field scattering and passive and active loads. The representation is made in terms of both open-circuit impedance parameters and short-circuit admittance parameters. Variational formulas for all parameters are given. Specialisation to the case of planewave scattering is made. Relationships between scattering parameters and commonly defined antenna parameters are given. Several examples of applications of the theory are included.