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Review of electromagnetic field calculations by digital linear filtering
Author(s) -
Verma Rajni K.
Publication year - 1982
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/rs017i005p01067
Subject(s) - bessel function , convolution (computer science) , hankel transform , digital filter , filter (signal processing) , decimal , fourier transform , mathematics , field (mathematics) , cylindrical harmonics , electromagnetic field , mathematical analysis , algorithm , computer science , physics , arithmetic , quantum mechanics , pure mathematics , classical orthogonal polynomials , gegenbauer polynomials , orthogonal polynomials , machine learning , artificial neural network , computer vision
The determination of electromagnetic fields over layered earth structures involves evaluation of the Hankel transform integrals. The classical method of numerical integration is very tedious, as it involves evaluating infinite integrals containing product functions with Bessel functions that are oscillatory and thus time consuming even on high‐speed digital computers. In contrast, the digital linear filter (convolution) method, which avoids Bessel function evaluations, is extremely rapid with regard to the ease with which it can be applied and to speed of calculations, and it provides accurate (five or more decimal accuracy) results. The speed of calculations can be further significantly increased while maintaining the same accuracy using a variable convolution approach. In some cases, the digital linear filter method has proved to be more rapid in calculations than the fast Fourier transform method.