Extraction of the Natural Poles of the Radio Scattered Field from a Multi-Port Channel Matrix

In this article, we introduce a novel approach termed the Higher-order Singular Value Decomposition Matrix Pencil Method, designed for the extraction of natural poles or complex natural frequencies inherent in the scattered electromagnetic field, as captured by the multi-port channel matrix in a distributed antennas system. This method not only identifies the shared natural poles or frequencies across all entries of the multi-port channel matrix but also calculates the residue of each pole for every entry. We test our proposed method on real radio frequency to extract the natural frequencies of the shadow radiation caused by the human body scattering impinging radio waves.