Electromagnetic Modal Inversion

The diagonalizing entire-structure driving power operator (ES-DPO) method for calculating external-incident-field-excited scattering characteristic modes (CMs), diagonalizing partial-structure driving power operator (PS-DPO) method for calculating lumped-port-driven transmitting CMs, and diagonalizing input power operator (IPO) method for calculating wave-port-fed transmitting energy-decoupled modes (DMs) are simply reviewed. Using the scattering CMs-based, transmitting CMs-based, and transmitting DMs-based modal expansions, this paper proposes some novel modal inversion methods for external-incident-field-excited scatterers, lumped-port-driven antennas, and wave-port-fed antennas. The modal inversion methods can use the modal field distributing in a local sampling region to invert the modal field distribution in the whole 3-D Euclidean space. This paper also abstracts the modal inversion methods for external-incident-field-excited scatterers, lumped-port-driven antennas, and wave-port-fed antennas into a unified modal inversion method, and the unified method is universal for any open linear electromagnetic structure. In addition, some valuable corollaries are derived from the modal inversion methods.