A Multi-Region Internally Combined Volume Surface Integral Equation for EM Analysis of Inhomogeneous Negative and Positive Permittivity Scatterers

Electromagnetic (EM) analyses of inhomogeneous scatterers with positive and negative permittivities enable the development and deployment of many emerging technologies. For example, such analyses are necessary for the characterization of exciton-plasmon interactions in the design of composite nanostructures as well as the radar signature characterization of hypersonic re-entry space vehicles engulfed by plasma. When the traditional volume integral equation (VIE) is used for these analyses, it yields an ill-conditioned linear system of equations (LSE); the iterative solution of this ill-conditioned LSE converges very slowly or fails to converge to the desired accuracy. Recently, an internally combined volume-surface integral equation (ICVSIE) technique has been proposed for the EM analyses of inhomogeneous negative permittivity plasma scatterers, which reside in a positive permittivity background medium [1] . This technique yields a well-conditioned LSE by artificially changing the sign of the permittivity of the background medium in which the polarization currents radiate. That said, the standard ICVSIE technique is valid for a scatterer containing only a negative permittivity region; it was not formulated for EM analysis of a scatterer containing both regions of negative and positive permittivity.