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Specific absorption rate in electrically coupled biological samples between metal plates
Author(s) -
Joines William T.,
Blackman Carl F.,
Spiegel Ronald J.
Publication year - 1986
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250070207
Subject(s) - materials science , wavelength , metal , specific absorption rate , radius , electric field , absorption (acoustics) , optics , dipole , intensity (physics) , electromagnetic field , coupling (piping) , coaxial , molecular physics , analytical chemistry (journal) , chemistry , physics , optoelectronics , composite material , antenna (radio) , telecommunications , chromatography , computer security , organic chemistry , electrical engineering , quantum mechanics , computer science , metallurgy , engineering
The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal‐plate spacings by using the method of images and induced dipole coupling. For a decrease in metal‐plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring‐sample spacing. The calculations are compared with measurements made with the aid of an array of 1‐in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations.