Full-wave reduced-order models for local computational analysis

An important class of electromagnetic design problems involves a fixed platform structure, which dominates the problem size, and a fixed design region that contains variable design structures. It has previously been observed that such problems can be efficiently modeled using a single frequency modular fast direct analysis (MFD) method. When the current distribution on the whole structure is needed, the MFD method has a solution complexity of at least O(N) at low frequencies, where N is the total number of unknowns. It is shown in this paper that the complexity of the design cycle can be reduced to be less than O(N) (i.e., o(N]) if only the current and/or field distributions within the design region are of interest, and the incident fields are prespecified and/or excited by sources localized to the design region.