New Mathematical Framework for Analyzing Electromagnetic Modes in Lossy Structures
Researchers have developed a time-reversal characteristic-mode decomposition method for analyzing electromagnetic structures that lose energy through material absorption and loading. The approach maintains mathematical stability and physical interpretability even in conditions where classical methods become singular or unreliable. This advancement could improve the design and analysis of antennas and other electromagnetic devices operating in realistic, lossy environments.
A new theoretical framework has been introduced for decomposing electromagnetic modes in reciprocal lossy structures using time-reversal principles. The method is grounded in a transmit-receive interpretation of reciprocity, where the far-field radiation pattern of a mode determines the time-reversed incident field needed to optimally couple energy back into that mode. Unlike classical characteristic-mode expansions, this antilinear formulation maintains radiation-power orthogonality even with material loss, lossy loading, or matched absorption present. The researchers derived equivalent formulations across multiple computational frameworks—scattering operators, T-matrices, and method-of-moments—connecting external wave descriptions with current-space and port-excitation descriptions. Numerical demonstrations using a lossy two-sphere system and a loaded folded antenna confirmed the approach's stability and power interpretability, particularly near exceptional points where classical methods fail.
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- arXiv physicsCenter
Time-Reversal Characteristic Modes of Lossy Reciprocal Structures
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