DocumentCode :
1516302
Title :
Closed-Form Uniform Asymptotic Expansions of Green´s Functions in Layered Media
Author :
Boix, Rafael Rodriquez ; Fructos, Ana L. ; Mesa, Francisco
Author_Institution :
Dept. of Electron. & Electromagn., Univ. of Seville, Seville, Spain
Volume :
58
Issue :
9
fYear :
2010
Firstpage :
2934
Lastpage :
2945
Abstract :
Far-field closed-form expressions are derived for spatial domain multilayered Green´s functions (GF). For the derivation of these far-field expressions, the spectral domain multilayered GF are approximated by means of the total least square algorithm (TLSA) in terms of the spectral variable u0=(kρ2-k02)1/2, and uniform asymptotic expansions are determined for the Sommerfeld integrals of the resulting TLSA approximations. Numerical results show that the far-field asymptotic expressions are accurate within 0.1% for distances between source and field points larger than one free-space wavelength. Also, it is shown that the hybrid use of the discrete complex image method and the TLSA in terms of the spectral variable kρ leads to near-field closed-form expressions of multilayered GF that are typically accurate within 0.1% for distances between source and field points smaller than one free-space wavelength. Therefore, the combination of the novel far-field asymptotic expressions and the well known near-field expressions makes it possible to compute multilayered GF with a great accuracy in the whole range of distances between source and field points, and in a wide range of frequencies.
Keywords :
Green´s function methods; computational electromagnetics; electromagnetic wave propagation; inhomogeneous media; integral equations; least squares approximations; Green function; Sommerfeld integrals; closed form uniform asymptotic expansion; far field expressions; layered media; total least square algorithm; Electrical capacitance tomography; Electromagnetic analysis; Frequency; Green´s function methods; Least squares approximation; Moment methods; Nonhomogeneous media; Physics; Postal services; Surface waves; Green´s functions; multilayered media; surface waves;
fLanguage :
English
Journal_Title :
Antennas and Propagation, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-926X
Type :
jour
DOI :
10.1109/TAP.2010.2052569
Filename :
5484681
Link To Document :
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