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Time domain near‐field to near‐field transformation using a spherical‐multipole approach
Author(s) -
Klinkenbusch L.
Publication year - 2011
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2011rs004670
Subject(s) - multipole expansion , spherical multipole moments , frequency domain , domain (mathematical analysis) , time domain , fourier transform , fast multipole method , physics , mathematical analysis , field (mathematics) , amplitude , fictitious domain method , finite difference time domain method , near and far field , mathematics , optics , computer science , quantum mechanics , pure mathematics , computer vision
The time domain electromagnetic field of an arbitrary localized radiating structure can be efficiently obtained by means of a time domain spherical‐multipole expansion valid outside a minimum sphere enclosing all radiating elements. The method is based on the Fourier transform of the frequency‐domain spherical‐multipole expansion and on a finite expansion of the spherical Hankel function of the 2nd kind leading to a triple sum of multipoles instead of the well‐known double sum in case of the frequency‐domain multipole expansion. It is shown that those time domain multipole amplitudes which are relevant only in the near‐field can be recursively deduced from the time domain amplitudes dominant in the far field. The latter can be obtained by a recently proposed spherical‐multipole based time domain near‐field to far‐field algorithm which has been shown to be particularly suited for the Finite‐Difference Time Domain (FDTD) method.